Vertical takeoff and landing aircraft

ABSTRACT

An aircraft includes a fuselage; a propulsion system including a power source and a vertical thrust electric fan oriented to generate thrust along a vertical direction and powered by the power source; and a wing extending from the fuselage and including the vertical thrust electric fan positioned at least partially therein. The wing includes a variable geometry assembly having partial wing assembly, the partial wing assembly including a frame and a first member, the partial wing assembly moveable generally along a longitudinal direction when the variable geometry assembly is moved between a forward thrust position and a vertical thrust position, the first member moveable relative to the frame to form an exhaust path for the vertical thrust electric fan.

RELATED APPLICATION

The present application is based upon and claims priority to U.S.Provisional Patent Application Ser. No. 62/535,444, filed on Jul. 21,2017.

FIELD

The present subject matter relates generally to an aircraft havingvertical takeoff and landing capabilities, and more specifically to anexhaust assembly for a vertical thrust fan of the aircraft.

BACKGROUND

Aircraft have been developed with a capability for performing verticaltakeoff and landings. Such a capability may allow for the aircraft toreach relatively rugged terrains and remote locations, where it may beimpractical or infeasible to construct a runway large enough to allowfor a traditional aircraft (lacking vertical takeoff capability) totakeoff or land.

Typically these aircraft that are capable of performing vertical takeoffand landings have engines and propulsors that are vectored to generateboth vertical thrust and forward thrust. These propulsors may berelatively large to generate an amount of thrust required for verticaltakeoff and landings, as well as for forward flight. However, such aconfiguration may create complications, as the propulsors are generallydesigned to be most efficient during one of vertical thrust operationsor forward thrust operations. Such may therefore lead to inefficiencieswithin the aircraft. Accordingly, a vertical takeoff and landingaircraft designed to address these inefficiencies would be useful.

BRIEF DESCRIPTION

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

In one embodiment of the present disclosure, an aircraft is provideddefining a vertical direction and a longitudinal direction. The aircraftincludes a fuselage; a propulsion system including a power source and avertical thrust electric fan oriented to generate thrust along thevertical direction and powered by the power source; and a wing extendingfrom the fuselage and including the vertical thrust electric fanpositioned at least partially therein. The wing includes a variablegeometry assembly having partial wing assembly, the partial wingassembly including a frame and a first member, the partial wing assemblymoveable generally along the longitudinal direction when the variablegeometry assembly is moved between a forward thrust position and avertical thrust position, the first member moveable relative to theframe to form an exhaust path for the vertical thrust electric fan.

In certain exemplary embodiments the partial wing assembly is a forwardpartial wing assembly, and wherein the variable geometry assemblyfurther includes an aft partial wing assembly, wherein the aft partialwing assembly is also moveable generally along the longitudinaldirection when the variable geometry assembly is moved between theforward thrust position and the vertical thrust position.

For example, in certain exemplary embodiments the vertical thrustelectric fan is substantially completely enclosed within the wing whenthe variable geometry assembly is in the forward thrust position, andwherein the vertical thrust electric fan is substantially completelyexposed when the variable geometry assembly is in the vertical thrustposition.

For example, in certain exemplary embodiments the aft partial wingassembly includes a frame and a first member movable relative to theframe to form at least in part the exhaust path for the vertical thrustelectric fan.

In certain exemplary embodiments the first member is configured to pivotdownwardly along the vertical direction when the variable geometryassembly is moved to the vertical thrust position.

In certain exemplary embodiments the vertical thrust electric fandefines a fan axis, wherein the first member of the partial wingassembly of the wing defines a first angle with the fan axis when thevariable geometry assembly is in the forward thrust position and asecond angle with the fan axis when the variable geometry assembly is inthe vertical thrust position, and wherein the first angle is greaterthan the second angle.

For example, in certain exemplary embodiments the first angle is betweenabout 75 degrees and about 105 degrees, and wherein second angle isbetween about −30 degrees and 75 degrees.

In certain exemplary embodiments the partial wing assembly furtherincludes a second member, wherein the first member is a bottom memberand wherein the second member is a top member, wherein the top member ismovable relative to the frame of the partial wing assembly to at leastpartially form an inlet path for the vertical thrust electric fan.

For example, in certain exemplary embodiments the top member isconfigured to pivot upwardly along the vertical direction when thevariable geometry assembly is moved to the vertical thrust position.

For example, in certain exemplary embodiments the vertical thrustelectric fan defines a fan axis, wherein the second member of thepartial wing assembly defines a first angle with the fan axis when thevariable geometry assembly is in the forward thrust position and asecond angle with the fan axis when the variable geometry assembly is inthe vertical thrust position, and wherein the first angle is betweenabout 75 degrees and about 105 degrees, and wherein second angle isbetween about 120 degrees and about 180 degrees.

In certain exemplary embodiments the first member of the partial wingassembly defines a length, wherein the vertical thrust electric fandefines a fan diameter, and wherein the length is at least about 75percent of the fan diameter.

In certain exemplary embodiments the vertical thrust electric fan is afirst vertical thrust electric fan of a plurality of vertical thrustelectric fans of the propulsion system, wherein the variable geometryassembly substantially completely encloses the plurality of verticalthrust electric fans when in the forward thrust position, and whereinthe variable geometry assembly substantially completely exposes theplurality of vertical thrust electric fans when in the vertical thrustposition.

In certain exemplary embodiments the wing includes a rail and anactuator, and wherein the frame of the partial wing assembly is movablealong the rail by the actuator.

In certain exemplary embodiments the partial wing assembly includes anactuator, and wherein the actuator is configured to move the firstmember downwardly along the vertical direction when the variablegeometry assembly is moved to the vertical thrust position.

In certain exemplary embodiments the wing is an aft wing, wherein thevertical thrust electric fan is a first vertical thrust electric fan,and wherein the aircraft further includes: a second wing coupled to andextending from the fuselage, wherein the propulsion system furtherincludes a second vertical thrust electric fan integrated into thesecond wing and oriented to generate thrust along the verticaldirection, the second wing including a variable geometry assembly havinga partial wing assembly, the partial wing assembly including a frame anda first member, the partial wing assembly of the second wing moveablegenerally along the longitudinal direction when the variable geometryassembly of the second wing is moved between a forward thrust positionand a vertical thrust position, the first member moveable relative tothe frame to form at least in part an exhaust path for the secondvertical thrust electric fan.

In certain exemplary embodiments the vertical thrust electric fan is afirst vertical thrust electric fan of a plurality of vertical thrustelectric fans of the propulsion system, and wherein the plurality ofvertical thrust electric fans are arranged along a length of the wing.

For example, in certain exemplary embodiments each of the plurality ofelectric fans are fixed in orientation within the wing.

In certain exemplary embodiments the hybrid electric propulsion systemfurther includes a combustion engine and a forward thrust propulsor,wherein the electric power source is an electric machine driven by thecombustion engine, and wherein the forward thrust propulsor isselectively or permanently mechanically coupled to the combustionengine.

In one exemplary embodiment of the present disclosure, a wing isprovided for an aircraft including a fuselage and a propulsion systemand defining a vertical direction and a longitudinal direction. The wingincludes a plurality of vertical thrust electric fans positioned atleast partially within the wing and arranged along a length of the wing;and a variable geometry assembly having partial wing assembly, thepartial wing assembly including a frame and a first member, the partialwing assembly moveable generally along the longitudinal direction whenthe variable geometry assembly is moved between a forward thrustposition and a vertical thrust position, the first member moveablerelative to the frame to form an exhaust path for the vertical thrustelectric fan.

In certain exemplary embodiments the partial wing assembly is a forwardpartial wing assembly, and wherein the variable geometry assemblyfurther includes an aft partial wing assembly, wherein the aft partialwing assembly is also moveable generally along the longitudinaldirection when the variable geometry assembly is moved between theforward thrust position and the vertical thrust position, and whereinthe aft partial wing assembly includes a frame and a first membermovable relative to the frame to form at least in part the exhaust pathfor the vertical thrust electric fan.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appended Figs.,in which:

FIG. 1 is a perspective view of an aircraft according to variousexemplary embodiments of the present disclosure.

FIG. 2 is a top, schematic view of the exemplary aircraft of FIG. 1 in avertical flight position.

FIG. 3 is a top, schematic view of the exemplary aircraft of FIG. 1 in aforward flight position.

FIG. 4 is a schematic view of a power source of the exemplary aircraftof FIG. 1.

FIG. 5 is a side, schematic, cross-sectional view of a wing inaccordance with an exemplary embodiment of the present disclosure as maybe incorporated into the exemplary aircraft of FIG. 1 in a forwardflight position.

FIG. 6 is a side, schematic, cross-sectional view of the exemplary wingof FIG. 5 in a vertical flight position.

FIG. 7 is a top, schematic view of an aircraft in accordance withanother exemplary embodiment of the present disclosure in a verticalflight position.

FIG. 8 is a top, schematic view of the exemplary aircraft of FIG. 7 in apartial vertical flight position.

FIG. 9 is a top, schematic view of a wing of an aircraft in accordancewith still another exemplary embodiment of the present disclosure in avertical flight position.

FIG. 10 is a side, schematic, cross-sectional view of the exemplary wingof FIG. 9 in the vertical flight position.

FIG. 11 is a side, schematic, cross-sectional view of the exemplary wingof FIG. 9 in a forward flight position.

FIG. 12 is a forward, schematic, cross-sectional view along a lengthwisedirection of the exemplary wing of FIG. 9 in the vertical flightposition.

FIG. 13 is a top, schematic view of an aircraft in accordance withanother exemplary embodiment of the present disclosure.

FIG. 14 is a flow diagram of a method for operating an aircraft inaccordance with an exemplary aspect of the present disclosure.

FIG. 15 is a flow diagram of a method for operating an aircraft inaccordance with another exemplary aspect of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to present embodiments of theinvention, one or more examples of which are illustrated in theaccompanying drawings. The detailed description uses numerical andletter designations to refer to features in the drawings. Like orsimilar designations in the drawings and description have been used torefer to like or similar parts of the invention.

As used herein, the terms “first”, “second”, and “third” may be usedinterchangeably to distinguish one component from another and are notintended to signify location or importance of the individual components.

The terms “forward” and “aft” refer to relative positions within a gasturbine engine or vehicle, and refer to the normal operational attitudeof the gas turbine engine or vehicle. For example, with regard to a gasturbine engine, forward refers to a position closer to an engine inletand aft refers to a position closer to an engine nozzle or exhaust.

The terms “upstream” and “downstream” refer to the relative directionwith respect to fluid flow in a fluid pathway. For example, “upstream”refers to the direction from which the fluid flows, and “downstream”refers to the direction to which the fluid flows.

The terms “coupled,” “fixed,” “attached to,” and the like refer to bothdirect coupling, fixing, or attaching, as well as indirect coupling,fixing, or attaching through one or more intermediate components orfeatures, unless otherwise specified herein.

The singular forms “a”, “an”, and “the” include plural references unlessthe context clearly dictates otherwise.

Approximating language, as used herein throughout the specification andclaims, is applied to modify any quantitative representation that couldpermissibly vary without resulting in a change in the basic function towhich it is related. Accordingly, a value modified by a term or terms,such as “about”, “approximately”, and “substantially”, are not to belimited to the precise value specified. In at least some instances, theapproximating language may correspond to the precision of an instrumentfor measuring the value, or the precision of the methods or machines forconstructing or manufacturing the components and/or systems. Forexample, the approximating language may refer to being within a 10percent margin.

Here and throughout the specification and claims, range limitations arecombined and interchanged, such ranges are identified and include allthe sub-ranges contained therein unless context or language indicatesotherwise. For example, all ranges disclosed herein are inclusive of theendpoints, and the endpoints are independently combinable with eachother.

The present disclosure is generally related to a vertical takeoff andlanding aircraft having an electric, or hybrid electric, propulsionsystem with a vertical thrust electric fan positioned on or within awing of the aircraft. The wing includes structural components forincreasing an efficiency of the plurality of vertical thrust electricfans. More particularly, the wing includes a variable geometry assemblyhaving partial wing assembly. The partial wing assembly includes a frameand a first member, and is moveable generally along the longitudinaldirection when the variable geometry assembly is moved between a forwardthrust position and a vertical thrust position. Further, the firstmember is moveable relative to the frame to form an exhaust path for thevertical thrust electric fan.

Moreover, in certain embodiments the partial wing assembly may be aforward partial wing assembly, and the variable geometry assembly mayfurther include an aft partial wing assembly. The aft partial wingassembly may similarly include a frame and a first member, and is maysimilarly be moveable generally along the longitudinal direction whenthe variable geometry assembly is moved between a forward thrustposition and a vertical thrust position. Further, the first member ofthe aft partial wing assembly may be moveable relative to the frame toalso form at least in part the exhaust path for the vertical thrustelectric fan.

For example, in at least certain exemplary embodiments, the firstmembers of the forward and aft partial wing assemblies may each bepositioned at a bottom side of the respective partial wing assemblies(e.g., configured as a bottom member), and may further be configured topivot downwardly when the variable geometry assembly is moved to thevertical thrust position.

In such a manner, the first members may form a diffusion flowpath for anairflow from the vertical thrust electric fan, the diffusion flowpathdefining a diffusion area ratio (a ratio of an exhaust cross-sectionalarea to an inlet cross-sectional area) greater than 1:1, and less thanabout 2:1, such that the vertical thrust electric fan may define arelatively high power loading (a measure of an amount of thrust producedper unit of power applied) during operation. Such may allow forinclusion of a smaller vertical thrust fan to provide a necessary amountof vertical thrust for the aircraft, leading to an overall moreefficient aircraft.

Referring now to the drawings, wherein identical numerals indicate thesame elements throughout the Figs. (“Figs.”), FIGS. 1 through 3 depictan aircraft 10 in accordance with various embodiments of the presentdisclosure. More specifically, FIG. 1 provides a perspective view of theexemplary aircraft 10; FIG. 2 provides a top, schematic view of theexemplary aircraft 10 of FIG. 1 in a vertical thrust configuration; andFIG. 3 provides a top, schematic view of the exemplary aircraft 10 ofFIG. 1 in a forward thrust configuration. As shown in FIGS. 1 through 3collectively, the aircraft 10 defines a longitudinal direction L (and alongitudinal centerline 12 that extends therethrough), a verticaldirection V, and a transverse direction T. Additionally, the aircraft 10defines a port side 14 and an opposite starboard side 16.

The aircraft 10 includes a fuselage 18 extending between a forward end20 and an aft end 22 generally along the longitudinal centerline 12 ofthe aircraft 10. The aircraft 10 additionally includes one or morewings, each extending from the fuselage 18. More specifically, for theembodiment depicted the aircraft 10 includes four wings attached to orformed integrally with the fuselage 18. Specifically, for the embodimentdepicted, the aircraft 10 includes a first wing, a second wing, a thirdwing, and a fourth wing, or more particularly an aft starboard wing 24,an aft port wing 26, a forward starboard wing 28, and a forward portwing 30, and. Each of these wings 24, 26, 28, 30 is attached to, orformed integrally with, the fuselage 18 and extends from the fuselage 18outwardly generally along the transverse direction T (i.e., outwardlyrelative to the fuselage 18). It will be appreciated that although theforward port wing 30 and forward starboard wing 28 are depicted as beingseparate wings, in other embodiments, the forward port wing 30 andforward starboard wing 28 may be formed integrally, and togetherattached to the fuselage 18. Similarly, although the aft port wing 26and aft starboard wing 24 are depicted as being separate wings, in otherembodiments, the aft port wing 26 and aft starboard wing 24 may beformed integrally, and together attached the fuselage 18.

Although not depicted, in other embodiments, the aircraft 10 mayadditionally include one or more stabilizers, such as one or morevertical stabilizers, horizontal stabilizers, etc. Moreover, it will beappreciated, that although not depicted, in certain embodiments, one ormore of the wings and/or stabilizers (if included) may additionallyinclude flaps, such as leading-edge flaps or trailing edge flaps, forassisting with controlling the aircraft 10 during flight.

Referring still to FIGS. 1 through 3, the exemplary aircraft 10 furtherincludes a propulsion system 32 for providing the aircraft 10 with adesired amount of thrust during operation. Broadly speaking, theexemplary propulsion system 32 includes a plurality of vertical thrustelectric fans (or “VTE fans”) for generating vertical thrust duringcertain operations, a forward thrust propulsor 34 for generating forward(and optionally reverse) thrust during certain operations, and a powersource 36 for driving the plurality of VTE fans and the forward thrustpropulsor 34. Additionally, for the embodiment depicted, the propulsionsystem 32 includes an electric communication bus 38 for, e.g., providingelectrical power from the power source 36 to the plurality of VTE fans.

More specifically, for the embodiment depicted, the power source 36includes a combustion engine 40, an electric machine 42, and an electricenergy storage unit 44. More specifically, referring now also to FIG. 4,a schematic view is provided of the exemplary combustion engine 40 ofthe power source 36 of the propulsion system 32 described above withreference to FIGS. 1 through 3. As is depicted, the combustion engine 40is configured to mechanically drive the forward thrust propulsor 34.More specifically, the forward thrust propulsor 34 is selectively orpermanently mechanically coupled to the combustion engine 40.Additionally, the combustion engine 40 is coupled to the electricmachine 42. Accordingly, in at least certain embodiments, the combustionengine 40 may drive the electric machine 42 such that the electricmachine 42 may generate electrical power. In such a manner, the electricmachine 42 may be configured as an electric generator, and the powersource 36 may generally be referred to as a “hybrid-electric powersource.” Further, with such an exemplary embodiment the electric machine42 may provide the electrical power to, e.g., the plurality of VTE fansduring at least certain operations of the aircraft, to the electricenergy storage unit 44, or both. In such a manner, the plurality of VTEfans may be driven by the power source 36, and more particularly, may bedriven at least in part by the electric machine 42.

Additionally, the electric energy storage unit 44 may be a battery orother suitable component for storing electrical power. The electricenergy storage unit 44 may receive electrical power from, e.g., theelectric machine 42 (operating as an electric generator), and storeelectrical power for use during operation of the aircraft 10. Forexample, the electric energy storage unit 44 may receive and storeelectrical power from the electric machine 42 (operating as an electricgenerator) during certain operations, and subsequently provideelectrical power to the plurality of VTE fans during other operations.Additionally, in still other operations, the electric energy storageunit 44 may provide electrical power back to the electric machine 42 to,e.g., power the aft fan for short durations, power the combustion engine40 during emergency operations, or add power to the forward thrustpropulsor 34 and/or to the combustion engine 40 during high power demandoperations. Accordingly, with such exemplary embodiment, the electricmachine 42 may further be configured as an electric motor.

More specifically, referring particularly to FIG. 4, for the embodimentdepicted, the combustion engine 40 is a turboshaft engine. Theturboshaft engine includes in serial flow order, a compressor sectionincluding a low pressure compressor 62 and a high pressure compressor64, a combustion section 66, and a turbine section including a highpressure turbine 68 and a low pressure turbine 70. During operation, aflow of air is received within the compressor section and isprogressively compressed as it flows therethrough, i.e., as it flowsfrom the low pressure compressor 62 to the high pressure compressor 64.The compressed air is then provided to the combustion section 66 whereit is mixed with fuel and burned to generate hot combustion gas. Theaircraft 10 further includes a fuel tank 71 for providing the fuel tothe combustion section 66 (see FIGS. 2 and 3).

The hot combustion gas is expanded through the turbine section whererotational energy is extracted therefrom. Specifically, the hotcombustion gas rotates the high pressure turbine 68 and the low pressureturbine 70 as the gas flows therethrough and is expanded. As is depictedin phantom, these components may be enclosed within a casing 72 within,e.g., the fuselage 18 of the aircraft 10. Although not depicted, the hotcombustion gas may be exhausted, e.g., to atmosphere, from the lowpressure turbine 70.

Also for the embodiment depicted, the high pressure turbine 68 isconnected to the high pressure compressor 64 through a high pressureshaft or spool 74, such that a rotation of the high pressure turbine 68additionally rotates the high pressure compressor 64. Similarly, the lowpressure turbine 70 is connected to the low pressure compressor 62through a low pressure shaft or spool 76, such that rotation of the lowpressure turbine 70 additionally rotates the low pressure compressor 62.

It will be appreciated, however, that the exemplary turboshaft enginedepicted in FIG. 4 is provided by way of example only. In otherexemplary embodiments, the turboshaft engine may have any other suitableconfiguration. For example, in other embodiments, the turboshaft enginemay include any other suitable number of compressors and/or any othersuitable number of turbines. Further, in still other embodiments, thecombustion engine may be any other suitable combustion engine, such as arotary or internal combustion engine.

Referring still to FIG. 4, the low pressure shaft 76 additionally drivesan output shaft. More specifically, for the embodiment of FIG. 4, thelow pressure shaft 76 additionally drives a first output shaft, or aforward output shaft 78, of the turboshaft engine and further drivessecond output shaft, or an aft output shaft 80 of the turboshaft engine.The forward output shaft 78 extends to the electric machine 42.Accordingly, rotation of the turboshaft engine provides, at least duringcertain operations, rotational energy to the electric machine 42 via theforward output shaft 78. The electric machine 42, in turn, is configuredto convert the rotational energy to generate electrical power. Morespecifically, it will be appreciated that at least certain embodimentsof the electric machine 42, such as the embodiment shown, may generallyinclude a rotor 82 and a stator 84. The rotational energy of theturboshaft engine is provided via the forward output shaft 78 andconfigured to rotate the rotor 82 of the electric machine 42 relative tothe stator 84. Such relative movement may generate electrical power.

Inclusion of a turboshaft engine and electric machine 42 in accordancewith such an exemplary embodiment may allow for the electric powersource 36 to generate a relatively high amount of electric power and toprovide such electric power to the plurality of VTE fans of thepropulsion system 32.

As is briefly discussed above, the turboshaft engine further drives theforward thrust propulsor 34 of the hybrid electric propulsion system 32.For the embodiment depicted, the forward thrust propulsor 34 iscomprises a fan 86 coupled to a fan shaft 88. The aft output shaft 80 ofthe turboshaft engine is selectively mechanically coupled to orpermanently mechanically coupled to the fan shaft 88 to allow theturboshaft engine to drive the fan 86. More specifically, duringoperation, the aft output shaft 80 of the turboshaft engine may drivethe fan shaft 88 to rotate the fan 86 about a fan axis 90. Notably, theforward thrust propulsor 34 further includes an outer nacelle 92surrounding at least a portion of the fan 86. In such a manner, theforward thrust propulsor 34 may be referred to as a ducted fan.

It will further be appreciated that for the embodiment depicted, theforward thrust propulsor 34 is mounted to the fuselage 18 of theaircraft 10 at an aft end 22 of the aircraft 10. Although not depicted,the forward thrust propulsor 34 may include one or more struts, or otherstructural members, extending between the outer nacelle 92 and thefuselage 18 of the aircraft 10 to mount the forward thrust propulsor 34to the fuselage 18 of the aircraft 10. Moreover, the forward thrustpropulsor 34 is configured as a boundary layer ingestion fan defining aninlet 94 extending substantially 360 degrees around the fuselage 18. Insuch a manner, the forward thrust propulsor 34 may ingest a boundarylayer airflow over the fuselage 18, and may re-energize such airflow tocreate a forward thrust for the aircraft 10.

Further, the fan 86 of the forward thrust propulsor 34 includes aplurality of fan blades 96 coupled to a disk 98, with the disk 98coupled to the fan shaft 88. More specifically, for the embodimentdepicted, each of the plurality of fan blades 96 are rotatably coupledto the disk 98 about a respective pitch axis 100. The forward thrustpropulsor 34 further includes a pitch change mechanism 102 operable witheach of the plurality of fan blades 96 to rotate each of the pluralityof fan blades 96 about their respective pitch axes 100, e.g., in unison.Accordingly, for the embodiment depicted the forward thrust propulsor 34is configured as a variable pitch fan.

Referring still to FIG. 4, it will be appreciated that the exemplarypropulsion system 32 depicted further includes a coupling unit 106, withthe turboshaft engine selectively mechanically coupled to the forwardthrust propulsor 34 through the coupling unit 106. The coupling unit 106may be at least one of a clutch or a torque converter. Morespecifically, for the embodiment depicted, the coupling unit 106includes a clutch, and more specifically, includes a one-way clutch. Forexample, in certain embodiments, the one-way clutch may be a spragclutch.

For example, in certain exemplary embodiments, as is depicted inphantom, the forward thrust propulsor 34 may further include a driveelectric machine 104, or rather, a drive motor, coupled to the fan shaft88. The drive electric machine 104 may be electrically coupled to thepower source 36, such as to one or more of the electric machine 42 orelectric energy storage unit 44, through the electric communication bus38. The drive electric machine 104 may receive electrical power to drivethe fan 86 of the forward thrust propulsor 34 during, e.g., emergencyoperations. Inclusion of a one-way clutch in the coupling unit 106, suchas a sprag clutch, may allow for the drive electric machine 104 torotate the fan 86 without having to correspondingly rotate thecombustion engine 40 (i.e., turboshaft for the embodiment depicted).

It will be appreciated, however, that in other exemplary embodiments,the clutch may instead be a two-way clutch actuatable between an engagedposition and a disengaged position. When in the engaged position, thefan shaft 88 may rotate with the aft output shaft 80 of the turboshaftengine (via an intermediate shaft 108). By contrast, when in thedisengaged position, the aft output shaft 80 of the turboshaft enginemay rotate independently of the fan shaft 88. For example, in certainembodiments, the aircraft 10 may move the clutch to the disengagedposition during, e.g., vertical takeoff, vertical landing, or hoveroperations wherein forward thrust is not required from the forwardthrust propulsor 34. However, when the aircraft 10 transitions toforward thrust operations, such as cruise operations, the clutch may bemoved to the engaged position to allow the forward thrust propulsor 34to generate forward thrust for the aircraft 10.

Further, still, for the embodiment depicted in FIG. 4, the aircraft 10additionally includes a speed change mechanism 110, with turboshaftengine being mechanically coupled to the forward thrust propulsor 34through the speed change mechanism 110. More specifically, for theembodiment of FIG. 4, the speed change mechanism 110 is configured as agearbox. More specifically, still, for the embodiment of FIG. 4, thespeed change mechanism 110 is configured as a planetary gear box.

It will be appreciated, however, that in other exemplary embodiments,the exemplary aircraft, and more specifically, the exemplary hybridelectric propulsion system, may include any other suitable combustionengine and forward thrust propulsor. For example, in other embodiments,the combustion engine may instead be a turboshaft engine having anyother suitable configuration, an internal combustion engine, etc.Additionally, in other embodiments, the forward thrust propulsor may becoupled to the combustion engine in any other suitable manner. Forexample, in other embodiments, the forward thrust propulsor may be anelectrically driven propulsor, an unducted fan, etc. Further, althoughdepicted at an aft end 22 of the aircraft, in other embodiments, theforward thrust propulsor may instead be located at, e.g., a forward end20 of the aircraft, or any other suitable location.

Further, still, in other exemplary embodiments of the presentdisclosure, the propulsion system may include any other suitable powersource for driving the plurality of VTE fans and forward thrustpropulsor. For example, in other exemplary embodiments, the propulsionsystem may not be a “hybrid-electric propulsion system,” and instead maybe a purely electric propulsion system. With such an exemplaryembodiment, substantially all the power for the VTE fans and forwardthrust propulsor may be provided from the electric energy storage unit44.

Referring now back particularly to FIGS. 1 through 3, a first of theplurality of wings of the aircraft 10, and more particularly, the aftstarboard wing 24 depicted in FIG. 2 defines a length 48 (and alengthwise direction LW), and the propulsion system 32 includes a firstplurality of VTE fans 46 arranged along the length 48 of the aftstarboard wing 24, and more specifically, arranged substantiallylinearly along the length 48 of the aft starboard wing 24 (i.e., acenter/axis of each of the first plurality of VTE fans 46 arranged in asubstantially straight line along the length 48 of the aft starboardwing 24). More specifically, still, it will be appreciated that for theembodiment depicted, the first plurality of VTE fans 46 are integratedinto the aft starboard wing 24 and oriented to generate thrust generallyalong the vertical direction V. In such a manner, each of the firstplurality of VTE fans 46 are vertical lift fans, and as will bediscussed in more detail below, are fixed in position such that they areonly capable of generating thrust generally along the vertical directionV of the aircraft 10. As will be discussed in greater detail below, eachof the first plurality of VTE fans 46 is electrically coupled to thepower source 36 to receive electrical power from, e.g., the electricmachine 42 or the electric energy storage unit 44.

It will be appreciated, that as used herein, the term “along thevertical direction V of the aircraft 10” refers to a vertical directiondefined by a normal orientation of the aircraft 10. For example, if theaircraft 10 is, e.g., tilted forward during certain operations, thefirst plurality of VTE fans 46 may provide thrust in a direction that isstill along the vertical direction of the aircraft 10, but tiltedrelative to an absolute vertical direction. Additionally, in thiscontext, the term “generally” refers to being within about thirtydegrees of the vertical direction V of the aircraft 10, such as withinabout fifteen degrees of the vertical direction V.

Additionally, for the embodiment depicted, the first plurality of VTEfans 46 includes at least three VTE fans 46, and more specifically,includes four VTE fans 46. However, in other embodiments, the firstplurality of VTE fans 46 may instead include any other suitable numberof VTE fans 46, such as two, five or more VTE fans 46. In certainembodiments, each of the first plurality of VTE fans 46 may beconfigured in the same manner as one another, or alternatively at leastone of the first plurality of VTE fans 46 may be configured differently(e.g., variable pitch or fixed pitch, variable speed or fixed speed,etc.).

Notably, by distributing the first plurality of VTE fans 46 along thelength 48 of the aft starboard wing 24, the lift forces on the aftstarboard wing 24 generated by the first plurality of VTE fans may bedistributed in a manner similar to a distribution of lift forcesgenerated on the aft starboard wing 24 during forward flight operations(i.e., left generated due to an airfoil cross-sectional shape of the aftstarboard wing 24). In such a manner, a structural frame of the aftstarboard wing 24 (referred to as a body portion 114, below), may servea dual function of supporting the lift forces during vertical flightoperations, as well as supporting the lift forces during forward flightoperations. Such may generally result in a more efficiently constructedaircraft 10.

It will further be appreciated that the exemplary propulsion system 32includes a similar plurality of electric fans integrated into the otherwings 26, 28, 30 of the aircraft 10. Each of these electric fans aresimilarly oriented to generate thrust generally along the verticaldirection V of the aircraft 10, and in such a manner may therefore alsobe configured as VTE fans. More specifically, the propulsion system 32further includes a second plurality of VTE fans 52 integrated into theaft port wing 26 and arranged substantially linearly along a length ofthe aft port wing 26, a third plurality of VTE fans 54 integrated intothe forward starboard wing 28 and arranged substantially linearly alonga length of the forward starboard wing 28, and a fourth plurality of VTEfans 56 integrated into the forward port wing 30 and arrangedsubstantially linearly along a length of the forward port wing 30.

For the embodiment depicted, the second plurality of VTE fans 52includes four VTE fans, and the third and fourth pluralities of VTE fans54, 56 each include two VTE fans. It will be appreciated, however, thatin other exemplary embodiments, each of the respective pluralities ofVTE fans 46, 52, 54, 56 may have any other suitable number of VTE fansand further that in certain exemplary embodiments, each of the pluralityof VTE fans 46, 52, 54, 56 may be configured in substantially the samemanner as one another, or one or more of such pluralities of VTE fans46, 52, 54, 56 may be configured differently. For example, in certainexemplary embodiments, each of the first plurality of VTE fans 46,second plurality of VTE fans 52, third plurality of VTE fans 54 andfourth plurality of VTE fans 56 may be configured as variable speed,fixed pitch fans, or alternatively, may each be configured as variablespeed, variable pitch fans (the “variable speed” functionality describedbelow). Or, alternatively, only a select number of these VTE fans 46,52, 54, 56 may have such functionality.

Moreover, as is depicted most clearly in FIG. 2, the electriccommunication bus 38 electrically connects the power source 36, e.g.,the electric machine 42 and/or the electric energy storage unit 44 forthe embodiment depicted, to each of the pluralities of VTE fans 46, 52,54, 56. Notably, for the embodiment depicted, the electric communicationbus 38 includes a main controller 58 and a plurality of electric powercontrollers 60. The main controller 58 is electrically connected to boththe electric machine 42 and the electric energy storage unit 44 and isconfigured to, e.g., direct electrical power from one or both of theelectric machine 42 and electric energy storage unit 44 to each of thepluralities of VTE fans 46, 52, 54, 56. For example, in certainoperations, the main controller 58 may direct electrical power from theelectric machine 42 to each of the pluralities of VTE fans 46, 52, 54,56, may direct electrical power from the electric energy storage unit 44to each of the pluralities of VTE fans 46, 52, 54, 56, may directelectrical power from the electric machine 42 to the electric energystorage unit 44 (e.g., during forward flight), or may direct electricalpower from the electric energy storage unit 44 to the electric machine42 (e.g., during emergency operations or high power demand operations).Other operations are contemplated as well.

More specifically, the exemplary embodiment of FIG. 2 the electriccommunication bus 38 includes an electric power controller 60 for eachVTE fan (i.e., each VTE fan of the first plurality of VTE fans 46, ofthe second plurality of VTE fans 52, of the third plurality of VTE fans54, and of the fourth plurality of VTE fans 56). Additionally, each ofthe plurality of electric power controllers 60 is associated with oneVTE fan of the pluralities of VTE fans 46, 52, 54, 56. Morespecifically, still, the power source 36 is electrically coupled to eachVTE fan of the pluralities of VTE fans 46, 52, 54, 56 through therespective electric power controller 60. In such a manner, the electricpower controller 60 may modify the electric power provided from thepower source 36 to each respective VTE fan. Accordingly, for theembodiment shown, the propulsion system 32 includes twelve electricpower controllers 60, one for each of the twelve VTE fans includedwithin the propulsion system 32.

In certain exemplary embodiments, each of the electric power controllers60 may be one or more of a power converter, a power inverter, or a powertransformer. Accordingly, in certain exemplary embodiments, the electricpower controllers 60 may be configured to convert electrical powerreceived through the electric communication bus 38 from alternatingcurrent (“AC”) electrical power to direct current (“DC”) electricalpower, or vice versa, and further may be configured in at least certainembodiments to modify an amount of the electrical power (e.g., a voltageor a current) received through the electric communication bus 38 fromthe power source 36 before transferring such electrical power to arespective VTE fan.

Accordingly, in at least certain embodiments each of the electric powercontrollers 60 may modify an amount of electrical power provided to arespective VTE fan, which as will be appreciated, may allow for theaircraft 10, and more specifically may allow for the main controller 58,to modify a rotational speed of each VTE fan of the pluralities of VTEfans 46, 52, 54, 56. For example, each of the electric power controllers60 may be operably coupled to the main controller 58 through, e.g., awired or wireless communication bus (not shown), such that the maincontroller 58 may control the electrical power provided to each of theindividual VTE fans.

Accordingly, it will be appreciated that in at least certain embodimentseach VTE fan of the pluralities of VTE fans 46, 52, 54, 56 may bevariable speed fans. Accordingly, by modifying an amount of electricalpower provided to each VTE fan through a respective electric powercontroller 60, the aircraft 10 may modify a rotational speed of therespective VTE fan, and therefore an amount of vertical thrust providedby the respective VTE fan. In such a manner, the aircraft 10 may allowfor more dynamic control during vertical takeoff and landing, or othervertical thrust operations.

It should be appreciated, however, that in other exemplary embodiments,the aircraft 10, or rather, the electric communication bus 38 may notinclude an electric power controller 60 for each of the individual VTEfans. Instead, for example, in other embodiments, the electriccommunication bus 38 may include a single electric power controller 60for each of the individual pluralities of VTE fans 46, 52, 54, 56. Instill other embodiments, however, any other suitable configuration maybe provided.

Referring particularly to FIGS. 2 and 3, it will be appreciated thateach of the wings 24, 26, 28, 30 generally includes a structural bodyportion 114 (FIG. 2) and one or more components movable to selectivelyexpose the plurality of VTE fans included therein. For the embodimentshown, the one or more components include a variable geometry assembly116 movable relative to the body portion 114 of the respective wingbetween a vertical thrust position (see FIG. 2) and a forward thrustposition (see FIG. 3) to facilitate a vertical takeoff and landing ofthe aircraft 10, or other vertical thrust operations of the aircraft 10.

For example, referring particularly to the aft starboard wing 24, forthe embodiment depicted, the aft starboard wing 24, which is coupled to,and extends from, the fuselage 18, includes the structural body portion114 (see particularly FIG. 2) and the variable geometry assembly 116.The variable geometry assembly 116 at least partially covers andencloses at least one VTE fan of the first plurality of VTE fans 46 whenin the forward thrust position (FIG. 3) and at least partially exposesthe at least one VTE fan of the first plurality of VTE fans 46 when inthe vertical thrust position (FIG. 2). More specifically, for theembodiment shown, the variable geometry assembly 116 extends along thelength 48 of the aft starboard wing 24 and at least partially covers atleast two VTE fans of the first plurality of VTE fans 46 when in theforward thrust position and at least partially exposes the at least twoVTE fans of the first plurality of VTE fans 46 when in the verticalthrust position.

More specifically, still, for the embodiment of FIGS. 2 and 3, thevariable geometry assembly 116 includes a partial wing assembly at leastpartially covering at least one VTE fan of the first plurality of VTEfans 46 when the variable geometry assembly 116 is in the forward thrustposition. More specifically, for the embodiment depicted, the partialwing assembly at least partially covers each of the first plurality ofVTE fans 46 when the variable geometry assembly 116 is in the forwardthrust position. For the embodiment depicted, the partial wing assemblyis a forward partial wing assembly 118, the forward partial wingassembly 118 extending along the length 48 of the aft starboard wing 24(i.e., in the lengthwise direction LW of the aft starboard wing 24) andat least partially covering each of the first plurality of VTE fans 46when the variable geometry assembly 116 is in the forward thrustposition. Moreover, for the embodiment depicted, the variable geometryassembly 116 additionally includes an aft partial wing assembly 120. Forthe embodiment depicted, the aft partial wing assembly 120 also extendsalong the length 48 of the aft starboard wing 24 and at least partiallycovers each of the first plurality of VTE fans 46 when the variablegeometry assembly 116 is in the forward thrust position. Notably, whenthe variable geometry assembly 116 is in the forward thrust position,the forward partial wing assembly 118 and aft partial wing assembly 120may each be referred to as being in a retracted position. Conversely,when the variable geometry assembly 116 is in the vertical thrustposition, the forward partial wing assembly 118 and aft partial wingsimile 120 may each be referred to as being in an extended position.

Referring now also to FIGS. 5 and 6, cross-sectional views are providedof the aft starboard wing 24. More specifically, FIG. 5 provides across-sectional view of the aft starboard wing 24 through Line 5-5 inFIG. 3 (with the variable geometry assembly 116 in the forward thrustposition); and FIG. 6 provides a cross-sectional view of the aftstarboard wing 24 through Line 6-6 in FIG. 2 (with the variable geometryassembly 116 in the vertical thrust position).

As will be appreciated, the aircraft 10 further defines a horizontaldirection. The horizontal direction, as used herein refers to generallyto any direction perpendicular to the vertical direction V, andtherefore may also be thought of as a horizontal plane. As will beappreciated, the longitudinal direction L extends within, and thereforeis parallel to the horizontal direction/horizontal plane. The variablegeometry assembly 116 is movable generally along the horizontaldirection between the forward thrust position and the vertical thrustposition, and more specifically, for the embodiment depicted, is movablegenerally along the longitudinal direction L. More specifically still,it will be appreciated that the aft starboard wing 24 defines awidthwise direction W perpendicular to the lengthwise direction LW, andfor the embodiment shown, the variable geometry assembly 116 is movablegenerally along the widthwise direction W of the aft starboard wing 24.(It should be appreciated, however, that in other embodiments, aspectsof the variable geometry assembly 116 may instead move or translate inany other suitable direction along the horizontal plane. Additionally,although the widthwise direction W and Longitudinal direction L aredepicted, e.g., in FIGS. 5 and 6 as being generally parallel to oneanother, in certain embodiments, these two directions W, L may define anangle relative to one another.)

More specifically, the forward partial wing assembly 118 is positionedgenerally at a forward side of the aft starboard wing 24 and is movablegenerally along the horizontal direction when the variable geometryassembly 116 is moved between the forward thrust position and verticalthrust position. Particularly for the embodiment depicted, the forwardpartial wing assembly 118 moves forward generally along the longitudinaldirection L (and more specifically, along the widthwise direction W)when the variable geometry assembly 116 is moved to the vertical thrustposition (FIGS. 2, 6) from, e.g., the forward thrust position (FIGS. 3,5).

By contrast, the aft partial wing assembly 120 is positioned generallyat an aft side of the aft starboard wing 24. Similar to the forwardpartial wing assembly 118, however, the aft partial wing assembly 120 ismovable generally along the horizontal direction when the variablegeometry assembly 116 is moved between the forward thrust position andvertical thrust position. More specifically, for the embodimentdepicted, the aft partial wing assembly 120 moves aft generally alongthe longitudinal direction L (and more specifically, along the widthwisedirection W) when the variable geometry assembly 116 is moved to thevertical thrust position (FIGS. 2, 6) from, e.g., the forward thrustposition (FIGS. 3, 5).

Accordingly, as stated, and as will be appreciated from FIGS. 3 and 5,when the variable geometry assembly 116 is in the forward thrustposition (and the forward and aft partial wing assemblies 118, 120 ofthe variable geometry assembly 116 are in retracted positions), theforward and aft partial wing assemblies 118, 120 of the variablegeometry assembly 116 each at least partially enclose at least one VTEfan of the first plurality of VTE fans 46, and together substantiallycompletely enclose each of the first plurality of VTE fans 46 within theaft starboard wing 24. In such a manner, each of the first plurality ofVTE fans 46 are substantially completely enclosed within the aftstarboard wing 24 when the variable geometry assembly 116 is in theforward thrust position.

By contrast, as will be appreciated from FIGS. 2 and 6, when thevariable geometry assembly 116 is in the vertical thrust position (andthe forward and aft partial wing assemblies 118, 120 of the variablegeometry assembly 116 are in extended positions), the forward and aftpartial wing assemblies 118, 120 of the variable geometry assembly 116each at least partially expose at least one VTE fan of the firstplurality of VTE fans 46, and together substantially completely exposeeach of the first plurality of VTE fans 46 within the aft starboard wing24. In such a manner, each of the first plurality of VTE fans 46 aresubstantially completely exposed when the variable geometry assembly 116is in the vertical thrust position. Notably, as used herein, the term“exposed” with respect to a VTE fan refers to such fan having asubstantially open inlet and a substantially open exhaust (with theexception of any exhaust flowpath components, such as diffusion assemblycomponents, described below), such that the fan may receive a flow ofair substantially freely and exhaust such flow of air substantiallyfreely.

It will be appreciated, however, that in other exemplary embodiments,the variable geometry assembly 116 may not substantially completelyenclose each of the first plurality of VTE fans 46 when in the forwardthrust position. For example, in certain exemplary embodiments, thevariable geometry assembly 116 may only partially enclose one or more ofthe first plurality of VTE fans 46 when in the forward thrust position.In such a manner, the aircraft 10 may be configured for relativelyefficient forward flight while one or more of the first plurality of VTEfans 46 is at least partially exposed (either on an inlet side/top sideof the wing 24, outlet side/bottom side of the wing 24, or a combinationof both).

Further, it will be appreciated that as stated above the variablegeometry assembly 116, and more specifically the forward and aft partialwing assemblies 118, 120 of the variable geometry assembly 116, extendsubstantially along an entirety of the length 48 of the aft starboardwing 24. More particularly, each of the forward and aft partial wingassemblies 118, 120 defines a length 122 (see FIG. 3). The length 122 ofeach of these partial wing assemblies 118, 120 is, for the embodimentdepicted, greater than or equal to at least about seventy-five percent(75%) of the length 48 of the wing and less than or equal to about onehundred twenty-five percent (125%) of the length 48 of the aft starboardwing 24. More specifically, still, the length 122 of each of the partialwing assemblies 118, 120 is greater than, or substantially equal to, alength along the lengthwise direction LW from an inner edge of aninner-most VTE fan of the first plurality of VTE fans 46 to an outeredge of an outer-most VTE fan of the first plurality of VTE fans 46,such as up to about twenty-five percent greater or fifty percent greaterthan such length. It will be appreciated that in this context, the termsinner and outer are relative positional terms defined relative to thefuselage 18 of the aircraft 10.

In such a manner, the variable geometry assembly 116, and morespecifically, the forward and aft partial wing assemblies 118, 120 maybe moved, e.g., in unison, to expose each of the first plurality of VTEfans 46 arranged along the length 48 of the aft starboard wing 24 andintegrated into the aft starboard wing 24.

Moreover, it will be appreciated that for the embodiment depicted inFIGS. 1 through 3, each of the other wings (i.e., wings 26, 28, 30)similarly includes a variable geometry assembly 116 movable between aforward thrust position (FIG. 3) to substantially completely cover theplurality of VTE fans integrated therein (i.e., pluralities of fans 52,54, 56, respectively) and a vertical thrust position (FIG. 2) tosubstantially completely expose the plurality of VTE fans integrated thetherein (again, i.e., pluralities of fans 52, 54, 56, respectively).Each of the variable geometry assemblies 116 of these wings 26, 28, 30may be configured in substantially the same manner as the variablegeometry assembly 116 of the aft starboard wing 24 described above, oralternatively may be configured in any other suitable manner.

It should be appreciated, however, that in other exemplary embodiments,one or more of the wings of the aircraft 10 may have a variable geometryassembly 116 configured in any other suitable manner. For example,referring now to FIGS. 7 and 8, an aircraft 10 in accordance withanother exemplary embodiment of the present disclosure is provided. Theexemplary aircraft 10 of FIGS. 7 and 8 may be configured insubstantially the same manner as exemplary aircraft 10 described abovewith reference to FIGS. 1 through 6. Accordingly, the same or similarnumbers may refer to the same or similar parts.

For example, the aircraft 10 generally includes a fuselage 18 and apropulsion system 32 having a power source 36. Moreover, the aircraft 10includes a plurality of wings extending from, and couple to, thefuselage 18. For example, the plurality of wings includes a forwardstarboard wing 28, an aft starboard wing 24, a forward port wing 30 andan aft port wing 26. The propulsion system 32 includes a plurality ofVTE fans driven by the power source 36, and more particularly, includesa first plurality of VTE fans 46 arranged along a length 48 of the aftstarboard wing 24, a second plurality of VTE fans 52 arranged along alength of the aft port wing 26, a third plurality of VTE fans 54arranged along a length of the forward starboard wing 28, and a fourthplurality of VTE fans 56 arranged along a length of the forward portwing 30.

Further, each of the wings includes one or more components forselectively exposing the respective plurality of VTE fans. Morespecifically, each of the wings includes a variable geometry assembly116 movable between a forward thrust position and a vertical thrustposition to at least partially cover up and at least partially exposethe respective pluralities of VTE fans arranged along the lengthsthereof, and more specifically integrated therein. However, for theembodiment depicted, each of these variable geometry assemblies 116 isoperable to selectively expose and/or cover less than all of therespective plurality of VTE fans arranged along the length of therespective wing.

For example, referring particularly to the aft starboard wing 24including the first plurality of VTE fans 46, the variable geometryassembly 116 includes a partial wing assembly, with the partial wingassembly at least partially covering less than all of the firstplurality of VTE fans 46 when the variable geometry assembly 116 is inthe forward thrust position. More specifically, for the embodiment ofFIGS. 7 and 8, the partial wing assembly is an inner partial wingassembly and the variable geometry assembly 116 further comprises anouter partial wing assembly (i.e., inner and outer relative to thefuselage 18 of the aircraft 10). More specifically still, the innerpartial wing assembly is an inner, forward partial wing assembly 118Aand the outer partial wing assembly is an outer, forward partial wingassembly 118B. The inner, forward partial wing assembly 118A and outer,forward partial wing assembly 118B are arranged sequentially along thelength 48 of the aft starboard wing 24 (more particularly, along thelengthwise direction LW of the aft starboard wing 24). For theembodiment depicted, the inner, forward partial wing assembly 118Adefines a length 122. The length 122 is less than or equal to aboutfifty percent (50%) of the length 48 of the aft starboard wing 24, andgreater than or equal to at least about ten percent (10%) of the length48 of the aft starboard wing 24. Further, for the embodiment depicted,the outer, forward partial wing assembly 118B defines a length 124 thatis substantially equal to the inner, forward partial wing assembly 118A.However, in other embodiments, the length 124 of the outer, forwardpartial wing assembly 118B may be different than the length 122 of theinner, forward partial and assembly 118A.

Further, still, for the embodiment depicted, the variable geometryassembly 116 of the aft starboard wing 24 further includes an inner, aftpartial wing assembly 120A and an outer, aft partial wing assembly 120B.The inner, aft partial wing assembly 120A is operable with the inner,forward partial wing assembly 118A to substantially completely cover orexpose a first portion 46A of the first plurality of VTE fans 46 and theouter, aft partial wing assembly 120B is operable with the outer,forward partial wing assembly 118B to substantially completely cover orexpose a second portion 46B of the first plurality of VTE fans 46.

It will be appreciated that, as is shown in FIG. 8, in certainembodiments the inner, forward partial wing assembly 118A and inner, aftpartial wing assembly 120A may be operable together and independently ofthe outer, forward partial wing assembly 118B and outer, aft partialwing assembly 120B. Accordingly, the variable geometry assembly 116 maybe movable to various “degrees” of vertical thrust positions, and asused herein, the term “vertical thrust position” with reference to thevariable geometry assembly 116 of a particular wing refers generally toa position in which at least one of the VTE fans of the respectiveplurality of VTE fans is at least partially exposed and capable ofgenerating vertical thrust.

For example, as is depicted, the variable geometry assembly 116 may bemovable to one or more partial vertical thrust positions, such as theposition shown, wherein the inner, forward partial wing assembly 118Aand inner, aft partial wing assembly 120A are in retracted positions tosubstantially completely cover the first portion 46A of the firstplurality of VTE fans 46, and wherein the outer, forward partial wingassembly 118B and outer, aft partial wing assembly 120B are in extendedpositions to substantially completely expose the second portion 46B ofthe first plurality of VTE fans 46. Such may allow for the firstplurality of VTE fans 46 to provide a reduced amount of vertical thrustduring, e.g., transitional flight conditions of the aircraft 10 (e.g.,transitioning from vertical flight to forward flight or vice versa).

Further, it will be appreciated that for the embodiment depicted, thevariable geometry assemblies 116 of each of the other wings, i.e., theaft port wing 26, forward starboard wing 28, and forward port wing 30,are depicted configured in a similar manner to the exemplary variablegeometry assembly 116 of the aft starboard wing 24. Notably, at leastcertain operations of the aircraft 10 described above with reference toFIGS. 7 and 8 will be described below with reference to FIGS. 14 and 15.

Further, still, it should be appreciated that although the exemplaryvariable geometry assemblies 116 depicted in FIGS. 7 and 8 generallyinclude two sets of partial wing assemblies arranged sequentially alongthe lengthwise directions of the respective wings, in other exemplaryembodiments, the variable geometry assemblies may include any othersuitable number of partial wing assembly sets (i.e., corresponding pairsof forward and aft partial wing assemblies) arranged sequentially alongthe lengthwise directions of the respective wings. For example, in otherexemplary embodiments, one or more of the variable geometry assemblies116 may include three sets of partial wing assemblies spaced along thelengthwise directions of the respective wings, four sets of partial wingassemblies arranged sequentially along the lengthwise directions of therespective wings, etc. Further, in certain exemplary embodiments, one ormore of the wings may include a variable geometry assembly having anindividual set of partial wing assemblies for each VTE fan of theplurality of VTE fans arranged along the length of such wing. Moreover,although for the embodiment depicted in FIGS. 7 and 8 the variablegeometry assemblies 116 of each wing includes the same number of partialwing assembly sets, in other embodiments, certain of the wings mayinclude a variable geometry assembly having a different number ofpartial wing assembly sets than others.

In such a manner, it will be appreciated that the embodiment shown inFIGS. 7 and 8 is by way of example only. Further, although for theembodiments of FIGS. 1 through 6 and FIGS. 7 and 8, the variablegeometry assemblies 116 of each of the wings of the aircraft 10generally include a forward partial wing assembly 118 and an aft partialwing assembly 120, in other embodiments, one or more of these variablegeometry assemblies 116 may instead include a single partial wingassembly (i.e., only one of a forward or aft partial wing assembly 118,120) movable to selectively expose or cover-up one or more of the VTEfans of a respective plurality of VTE fans. Further, in still otherexemplary embodiments, one or more of these variable geometry assemblies116 may have any other suitable configuration for selectively exposingand/or covering up one or more of the VTE fans of the respectiveplurality of VTE fans.

Referring back to FIGS. 2 and 3, generally, it will be appreciated thatan aircraft 10 in accordance with one or more exemplary aspects of thepresent disclosure may include features for increasing an efficiency ofthe VTE fans included with the propulsion system 32. More specifically,at least one of the wings, and optionally each of the wings, includingVTE fans arranged along a length thereof includes features for enhancingan inlet flowpath and/or exhaust flowpath of the plurality of VTE fansfor increasing an amount of thrust generated by such plurality of VTEfans. For example, in at least certain exemplary embodiments, at leastone of the wings including VTE fans arranged along a length thereof mayinclude features for defusing an airflow 130 downstream of one or moreof the respective VTE fans. As will be appreciated, and as will bediscussed in greater detail below, by including these diffusionfeatures, a higher power loading may be achieved for the VTE fans,resulting in an increased performance out of the VTE fan per disk area(i.e., increased performance for a given size/diameter of VTE fan). Suchmay result in the ability to include smaller VTE fans while providing adesired amount of vertical thrust for the vertical thrust operations ofthe aircraft 10. Additionally, such a benefit may permit thedistribution of a plurality of smaller VTE fans along the length of thewing, allowing for lifting forces generated therefrom to be more evenlydistributed along the length of the wing and further allowing for higheraspect ratio wings, each discussed in greater detail below.

More specifically, referring now to FIGS. 9 through 11, additional viewsof the exemplary aircraft 10 of FIGS. 1 through 6 are provided,including a wing having a diffusion assembly 126 in accordance with anexemplary embodiment of the present disclosure. Accordingly, the same orsimilar numbers may refer to the same or similar parts.

Referring specifically to FIG. 9, providing a close-up, schematic viewof the exemplary aircraft 10, and more specifically, of the exemplaryaft starboard wing 24 of the exemplary aircraft 10, the aft starboardwing 24 is depicted with the variable geometry assembly 116 in thevertical thrust position. Positioning the variable geometry assembly 116in the vertical thrust position may facilitate a vertical takeoff andlanding of the aircraft 10, or other vertical thrust operations. For theembodiment depicted, the aft starboard wing 24 further includes a bodyportion 114 and the variable geometry assembly 116 includes a partialwing assembly. The body portion 114, in turn, includes a rail 134 and aprimary actuator 136. A frame of the partial wing assembly is movably,or rather, slidably, coupled to the body portion 114 of the aftstarboard wing 24. More specifically, the frame of the partial wingassembly is movable along the rail 134 of the body portion 114 by theprimary actuator 136 of the body portion 114.

Further, for the embodiment depicted, the partial wing assembly is aforward partial wing assembly 118, the frame of the partial wingassembly is a forward frame 138, and the variable geometry assembly 116of the aft starboard wing 24 further includes an aft partial wingassembly 120. The aft partial wing assembly 120 similarly includes anaft frame 140, and is movable at least partially along the longitudinaldirection L. When the variable geometry assembly 116 is moved to avertical thrust position (shown; see also FIG. 10 below), the forwardand aft partial wing assemblies 118, 120 are moved generally forward andaft, respectively, to extended positions, and when the variable geometryassembly 116 is moved to a forward thrust position (see FIG. 11 below),the forward and aft partial wing assemblies 118, 120 are moved generallyaft and forward, respectively, to retracted positions. Moreover, as withthe forward partial wing assembly 118, the aft frame 140 of the aftpartial wing assembly 120 is also movably, or rather, slidably, coupledto the body portion 114 of the aft starboard wing 24. More specifically,the aft frame 140 of the aft partial wing assembly 120 is movable alongthe rail 134 of the body portion 114 by the primary actuator 136 of thebody portion 114.

For the embodiment depicted, the body portion 114 of the aft starboardwing 24 includes two primary actuators 136, with each of these primaryactuators 136 coupled to both the forward partial wing assembly 118 andthe aft partial wing assembly 120 to move the forward partial wingassembly 118 and aft partial wing assembly 120 between their respectiveretracted positions (when the variable geometry assembly 116 is in theforward thrust position) and extended positions (when the variablegeometry assembly 116 is in a vertical thrust position). The primaryactuators 136 may be electric actuators (e.g., including electricmotors), hydraulic actuators, pneumatic actuators, or any other suitableactuator for moving the forward and aft partial wing assemblies 118, 120generally along the longitudinal direction L in the manner describedherein.

Further, for the embodiment depicted, the body portion 114 of the aftstarboard wing 24 includes three rails 134, and each of the forwardpartial wing assembly 118 and aft partial wing assembly 120 includes aslide member 142 (depicted in phantom; see also FIGS. 10 and 11) coupledto its respective frame 140, with the slide member 142 movable along acorresponding rail 134. It will be appreciated, however, that in otherexemplary embodiments, the body portion 114 of the aft starboard wing 24may instead include any other suitable number of primary actuators 136,positioned at any other suitable location, and further may include anyother suitable number of rails 134 positioned at any other suitablelocation. For example, in other embodiments, the body portion 114 of theaft starboard wing 24 may include a single primary actuator 136 and asingle rail 134, two rails 134, three primary actuators 136, four rails134 and/or primary actuators 136, etc. Further, it will be appreciatedthat although the forward partial wing assembly 118 and aft partial wingassembly 120 are configured to move generally along the longitudinaldirection L, the body portion 114 of the aft starboard wing 24 isfixedly coupled to the fuselage 18, such that it remains stationaryrelative to the fuselage 18 during all operating conditions of theaircraft 10.

Reference will now be made particularly to FIGS. 10 and 11. FIGS. 10 and11 each provide a side, cross-sectional view of a VTE fan positionedwithin the aft starboard wing 24 of FIG. 9, taken along Line 11-11 ofFIG. 9. More specifically, FIG. 10 provides a side, cross-sectional viewof the aft starboard wing 24 with the variable geometry assembly 116 inthe vertical thrust position; and FIG. 11 provides a side,cross-sectional view of the aft starboard wing 24 with the variablegeometry assembly in the forward thrust position. As will be appreciatedfrom FIGS. 10 and 11, the first plurality of VTE fans 46 within the aftstarboard wing 24 are substantially completely enclosed within the aftstarboard wing 24 when variable geometry assembly 116 is in the forwardthrust position (FIG. 11). By contrast, the first plurality of VTE fans46, for the embodiment depicted, are substantially completely exposedwhen the variable geometry assembly 116 is in the vertical thrustposition (FIG. 10). Notably, as used herein, the term “exposed” withrespect to a VTE fan refers to such fan having a substantially openinlet and a substantially open exhaust (with the exception of anyexhaust flowpath components, such as diffusion assembly components,described below), such that the fan may receive a flow of airsubstantially freely and exhaust such flow of air substantially freely.

Moreover, referring first to the forward partial wing assembly 118, itwill be appreciated that the forward partial wing assembly 118 furthercomprises a first member 144. The first member 144 is movable relativeto the forward frame 138 of the forward partial wing assembly 118 toform an exhaust path 146 for at least one of the plurality of VTE fans46, and more particularly, is movable relative to the forward frame 138to form the exhaust path 146 for the least one of the first pluralityVTE fans 46 when the variable geometry assembly 116 is moved to thevertical thrust position. More specifically, still, for the embodimentdepicted, the first member 144 is movable relative to the forward frame138 to form the exhaust path 146 for each of the first plurality of VTEfans 46 when the variable geometry assembly 116 is moved to the verticalthrust position. Accordingly, it will be appreciated that for theembodiment depicted, the first member 144 extends substantiallycontinuously along a length 48 of the aft starboard wing 24, adjacent toeach of the first plurality of VTE fans 46. More specifically, the firstmember 144 extends substantially from an inner edge (i.e., inner arelative to the fuselage 18 of the aircraft 10) of an inner-most VTE fanof the first plurality of VTE fans 46 to an outer edge (i.e., outerrelative to the fuselage 18 of the aircraft 10) of an outer-most VTE fanof the first plurality of VTE fans 46 (see FIG. 9).

Further, it will be appreciated that for the embodiment depicted, thefirst member 144 of the forward partial wing assembly 118 is configuredas a bottom member of the forward partial wing assembly 118, andaccordingly, is configured to move downwardly generally along thevertical direction V when the variable geometry assembly 116 is moved tothe vertical thrust position (and the forward partial wing assembly 118is moved to an extended position). For the embodiment depicted, thebottom member is pivotably coupled to the forward frame 138 of theforward partial wing assembly 118 at a joint 148, and accordingly, isconfigured to pivot downwardly generally along the vertical direction Vabout the joint 148 when the variable geometry assembly 116 is moved tothe vertical thrust position. In certain embodiments, the joint 148 mayextend continuously along a length of the first member 144, oralternatively, the joint 148 may include a plurality of individualjoints 134 spaced along the length of the first member 144 (i.e., alongthe lengthwise direction LW of the aft starboard wing 24).

Additionally, referring still to the forward partial wing assembly 118,for the exemplary embodiment depicted, the forward partial wing assembly118 further includes a second member 150 similarly movable relative tothe forward frame 138 of the forward partial wing assembly 118 to atleast partially define an inlet path 152 for the at least one VTE fan ofthe first plurality of VTE fans 46. More specifically, still, for theembodiment depicted, the second member 150 is movable relative to theforward frame 138 to form the inlet path 152 for each of the firstplurality of VTE fans 46 when the variable geometry assembly 116 ismoved to the vertical thrust position. Accordingly, it will beappreciated that for the embodiment depicted, the second member 150 alsoextends substantially continuously along the length 48 of the aftstarboard wing 24, adjacent to each of the first plurality of VTE fans46 (i.e., substantially from an inner edge of an inner-most VTE fan ofthe first plurality of VTE fans 46 to an outer edge of an outer-most VTEfan of the first plurality of VTE fans 46).

Moreover, for the embodiment shown, the second member 150 is a topmember and is configured to move upwardly generally along the verticaldirection V when the variable geometry assembly 116 is moved to thevertical thrust position. More particularly, as with the bottom member,the top member is pivotably coupled to the forward frame 138 of theforward partial wing assembly 118 at a joint 154, and accordingly, isconfigured to pivot upwardly generally along the vertical direction Vabout the joint 154 when the variable geometry assembly 116 is moved tothe vertical thrust position. As with the joint 148, the joint 154 maybe a continuous joint (i.e., extending substantially continuously alongthe length of the second member 150), or alternatively, may be aplurality of individual joints spaced along the length of the secondmember 150.

Referring still to FIGS. 10 and 11, the aft partial wing assembly 120similarly includes a first member 156 movable relative to the frame 140of the aft partial wing assembly 120 also to form at least in part theexhaust path 146 for the at least one VTE fan of the first plurality ofVTE fans 46, and more particularly, is movable relative to the frame 140to form at least in part the exhaust path 146 for the least one VTE fanof the first plurality VTE fans 46 when the variable geometry assembly116 is moved to the vertical thrust position. More specifically, still,for the embodiment depicted, the first member 156 of the aft partialwing assembly 120 is configured as a bottom member of the aft partialwing assembly 120, and accordingly, is configured to move downwardlygenerally along the vertical direction V when the aft partial wingassembly 120 is moved to the vertical thrust position. For theembodiment depicted, the bottom member is pivotably coupled to theforward frame 138 of the forward partial wing assembly 118 at a joint158, and accordingly, is configured to pivot downwardly generally alongthe vertical direction V about the joint 158 when the variable geometryassembly 116 is moved to the vertical thrust position.

Moreover, as with the forward partial wing assembly 118, for theexemplary embodiment depicted, the aft partial wing assembly 120 alsoincludes a second member 160 similarly movable relative to the frame 140of the aft partial wing assembly 120 to form at least in part the inletpath 152 for the at least one VTE fan of the first plurality of VTE fans46. More specifically, for the embodiment shown, the second member 160is a top member is configured to move upwardly generally along thevertical direction V when the variable geometry assembly 116 is moved tothe vertical thrust position. More particularly, as with the bottommember, the top member is pivotably coupled to the frame 140 of the aftpartial wing assembly 120 at a joint 162, and accordingly, is configuredto pivot upwardly generally along the vertical direction V about thejoint 162 when the variable geometry assembly 116 is moved to thevertical thrust position.

Notably, as with the first and second members 144, 150 of the forwardpartial wing assembly 118, the first and second members 156, 160 of theaft partial wing assembly 120 may each extend substantially continuouslyalong the length 48 of the aft starboard wing 24, such that they eachextend adjacent to each of the first plurality of VTE fans 46 (i.e.,substantially from an inner edge of an inner-most VTE fan of the firstplurality of VTE fans 46 to an outer edge of an outer-most VTE fan ofthe first plurality of VTE fans 46).

It should be appreciated, however, that in other exemplary embodiments,the first and second members 144, 150 of the forward partial wingassembly 118 and/or the first and second members 156, 160 of the aftpartial wing assembly 120 may not extend continuously in such a manner,and instead may have any other suitable configuration. For example, inother exemplary embodiments, one or more of such members 144, 150, 156,160 may include a plurality of individual members arranged sequentiallyalong the length 48 of the aft starboard wing 24. In such an embodiment,such plurality of members may operate independently of one another,and/or may operate in unison.

Regardless, referring still to FIGS. 10 and 11, it will be appreciatedthat for the embodiment depicted, each of the first and second members144, 150 of the forward partial wing assembly 118 and first and secondmembers 156, 160 of the aft partial wing assembly 120 are generallymovable between an open position (FIG. 10) and a closed position (FIG.11). When in the closed positions, the first and second members 144, 150of the forward partial wing assembly 118 and first and second members156, 160 of the aft partial wing assembly 120 together form an airfoilcross-sectional shape for the aft starboard wing 24. More specifically,when the first and second members 144, 150 of the forward partial wingassembly 118 and the first and second members 156, 160 of the aftpartial wing assembly 120 are in the closed positions, and the variablegeometry assembly 116 is in the forward thrust position (FIG. 11), thefirst and second members 144, 150 of the forward partial wing assembly118 and the first and second members 156, 160 of the aft partial wingassembly 120 each form at least in part the airfoil cross-sectionalshape for the aft starboard wing 24. By contrast, when the first andsecond members 144, 150 of the forward partial wing assembly 118 andfirst and second members 156, 160 of the aft partial wing assembly 120are in the open position, they each form at least in part the inlet path152 or the exhaust path 146 for the at least one VTE fan of the firstplurality of VTE fans 46.

Additionally, for the embodiment depicted the first member 144 and thesecond member 150 of the forward partial wing assembly 118 are movableby a first member actuator 164 and a second member actuator 166,respectively. For the embodiment depicted, the first member actuator 164and the second member actuator 166 are each configured as pneumaticactuators, and more specifically, as an inflatable bladder configured toreceive a pressurized flow of air to expand when the forward partialwing assembly 118 is moved to the forward thrust position in order topivot the first member 144 downwardly along the vertical direction V toits open position and the second member 150 upwardly along the verticaldirection V to its open position. Notably, in certain embodiments, thefirst and second members 144, 150 may be biased towards theclosed/retracted position, such that the first and second members 144,150 may be moved to their respective closed positions by deactivating ordeflating the respective (pneumatic) actuators 164, 166.

Accordingly, it will be appreciated that for the embodiment shown, thefirst member actuator 164 and the second member actuator 166 may operateindependently of the primary actuators 136 described above withreference to FIG. 9 configured to move the forward partial wing assembly118 and aft partial wing assembly 120 forward and aft, respectively,generally along the longitudinal direction L. Additionally, for theembodiment depicted, the first member actuator 164 is also operableindependently of the second member actuator 166. Accordingly, in certainembodiments, the first member 144 may be moved to its opened position,while the second member 150 remains in its closed position. Such may bebeneficial during, e.g., transitional operational conditions, such aswhen the aircraft 10 is transitioning from vertical flight to forwardflight.

As is also depicted, the first member 156 and second member 160 of theaft partial wing assembly 120 are similarly movable by a first memberactuator 164 and a second member actuator 166, respectfully. The firstmember actuator 164 of the aft partial wing assembly 120 may operate insubstantially the same manner as the first member actuator 164 theforward partial wing assembly 118. Additionally, the second memberactuator 166 of the aft partial wing assembly 120 may operate insubstantially the same manner as the second member actuator 166 of theaft partial wing assembly 120. Accordingly, will be appreciated that thefirst and second members 156, 160 of the aft partial wing assembly 120are also movable in the same manner as the first and second members 156,160 of the forward partial wing assembly 118, as described above.(Notably, in such a manner, the first and second members 156, 160 of theaft partial wing assembly 120 may also be biased towards theirrespective closed positions.)

Referring particularly to FIG. 10, as discussed above, the aft starboardwing 24 is depicted with the variable geometry assembly 116 in thevertical thrust position and the first members 144, 156 of the forwardand aft partial wing assemblies 118, 120 each in the open positions toform the exhaust path 146 for the at least one VTE fan. Notably, for theembodiment depicted, exhaust path 146 is a diffusion exhaust flowpathfor the VTE fan. In such a manner, it will be appreciated that thediffusion assembly 126, and more specifically, the first members 144,156, together define an inlet 128 and an outlet 132. As the exemplaryflowpath 146 is a diffusion flowpath, it will be appreciated that thediffusion assembly 126 may generally define an inlet cross-sectionalarea at the inlet 128 that is less than an outlet cross-sectional areaat the outlet 132. As will be discussed in more detail below, inclusionof the diffusion exhaust flowpath 146 may increase an overall efficiencyof the VTE fan.

Further, it will be appreciated that for the embodiment depicted, afirst VTE fan 46-1 (see also FIG. 9) of the first plurality of VTE fans46 (i.e., the at least one VTE fan depicted) defines a fan axis 170. Thefirst member 144 of the forward partial wing assembly 118 defines afirst angle 172 with the fan axis 170 when the variable geometryassembly 116 is in the forward thrust position and when the first member144 is in its closed position (FIG. 11), and further the first member144 of the forward partial wing assembly 118 defines a second angle 174with the fan axis 170 when the variable geometry assembly 116 is in thevertical thrust position and when the first member 144 is in its openposition (FIG. 10). (Notably, the first angle 172 and second angle 174,along with the angles noted below, are shown being defined withreference fan lines 170′, which are parallel to the actual fan axis 170,for convenience). As is evident, the first angle 172 is greater than thesecond angle 174. For example, the first angle 172, for the embodimentdepicted, is between about seventy-five (75) degrees and about onehundred and five (105) degrees, whereas the second angle 174 is betweenabout minus thirty (−30) degrees and about seventy-five (75) degrees.For example, in at least certain exemplary embodiments, the first angle172 may be between about eighty (80) degrees and one hundred (100)degrees, and the second angle 174 may be between about sixty (60)degrees and zero (0) degrees, such as between about forty-five (45)degrees and five (5) degrees. Alternatively, it will be appreciated thatinstead of being configured to form a portion of a diffusion exhaustflowpath, the first member 144 may instead be configured 24 to form anozzle exhaust flowpath. With such an exemplary embodiment, the secondangle 174 may be between zero (0) degrees and minus thirty (−30)degrees, such as less than about minus five (−5) degrees.

Notably, for the embodiment depicted, the first member 156 of the aftpartial wing assembly 120 also defines a first angle 176 with the fanaxis 170 when the variable geometry assembly 116 is in the verticalthrust position and when the first member 156 is in its open position(FIG. 10), and a second angle 178 with the fan axis 170 when thevariable geometry assembly 116 is in the forward thrust position andwhen the first member 156 is in its closed position (FIG. 11). The firstangle 176 defined between the first member 156 of the aft partial wingassembly 120 and the fan axis 170 may be substantially equal to thefirst angle 172 defined between the first member 144 of the forwardpartial wing assembly 118 and the fan axis 170, and similarly, thesecond angle 178 defined between the first member 156 of the aft partialwing assembly 120 and the fan axis 170 may be substantially equal to thesecond angle 174 defined between the first member 144 of the forwardpartial wing assembly 118 and the fan axis 170.

Further, for the embodiment depicted, the second member 150 of theforward partial wing assembly 118 similarly defines a first angle 180with the fan axis 170 when the variable geometry assembly 116 is in theforward thrust position and when the second member 150 is in its closedposition (FIG. 11), and further the second member 150 of the forwardpartial wing assembly 118 defines a second angle 182 with the fan axis170 when the variable geometry assembly 116 is in the vertical thrustposition and when the second member 150 is in its open position (FIG.10). As is evident, the first angle 180 is less than the second angle182. For example, the first angle 180, for the embodiment depicted, isbetween about sixty degrees and about one hundred and twenty degrees andthe second angle 182 is between about one hundred degrees and about onehundred and eighty degrees. More specifically, for the embodimentdepicted, the first angle 180 is between about seventy-five degrees andone hundred and ten degrees and the second angle 182 is between aboutone hundred and ten degrees and about one hundred and seventy degrees.

Notably, for the embodiment depicted, the second member 160 of the aftpartial wing assembly 120 also defines a first angle 181 with the fanaxis 170 when the variable geometry assembly 116 is in the verticalthrust position and when the first member 156 is in its open position(FIG. 10), and a second angle 183 with the fan axis 170 when thevariable geometry assembly 116 is in the forward thrust position andwhen the first member 156 is in its closed position (FIG. 11). The firstangle 181 defined between the second member 160 of the aft partial wingassembly 120 and the fan axis 170 may be substantially equal to thefirst angle 180 defined between the second member 150 of the forwardpartial wing assembly 118 and the fan axis 170, and similarly, thesecond angle 183 defined between the second member 160 of the aftpartial wing assembly 120 and the fan axis 170 may be substantiallyequal to the second angle 182 defined between the second member 150 ofthe forward partial wing assembly 118 and the fan axis 170.

Moreover, it will be appreciated that for the embodiment depicted, thefirst member 144 of the forward partial wing assembly 118 defines alength 184 and the first VTE fan 46-1 of the plurality of VTE fans 46(i.e., the at least one VTE fan depicted) defines a fan diameter 186.For the embodiment depicted, the length 184 of the first member 144 ofthe forward partial wing assembly 118 is at least about twenty-five (25)percent of the fan diameter 186. Similarly, the first member 156 of theaft partial wing assembly 120 defines a length 188. The length 188 ofthe first member 156 of the aft partial wing assembly 120 is also atleast about twenty-five (25) percent of the fan diameter 186. Moreover,the lengths 184, 188 of the first members 144, 156 of the forward andaft partial wing assemblies 118, 120, respectfully, may be up to aboutone hundred and fifty percent of the fan diameter 186.

Further, referring now briefly to FIG. 12, an aft-looking-forward,cross-sectional view is provided of the exemplary aft starboard wing 24described above with reference to FIGS. 10 and 11 generally along thelengthwise direction LW of the aft starboard wing 24. Briefly, FIG. 12shows that in at least certain exemplary embodiments, the diffusionassembly 126 may further include one or more features for enclosing theexhaust flowpath 146 defined at least in part by the first members 144,156 integrated into the forward partial wing assembly 118 and aftpartial wing assembly 120, respectfully. More specifically, for theembodiment depicted, the diffusion assembly 126 further includes aninner flap 190 and an outer flap 192. The inner flap 190 may extendgenerally along the longitudinal direction L, or widthwise direction W,between the first members 144, 146 at an inner end of the flowpath 146and the outer flap 192 may extend generally along the longitudinaldirection L, or widthwise direction W, between the first members 144,146 at an outer end of the flowpath 146. The inner flap 190 and outerflap 192 may include actuators similar to the first and second memberactuators 164, 166, or in accordance with any other suitableconfiguration. Further, it will be appreciated that the inner and outerflaps 190, 192 may be moved, e.g., along directional arrows 193, to anopen position (shown) from a closed position (directional arrowsprovided) when the variable geometry assembly 116 is moved to thevertical thrust position (shown).

Furthermore, it will be appreciated that although the embodiments shownin FIGS. 9 through 12 relate to the aft starboard wing 24 of theexemplary aircraft 10 described above with reference to FIGS. 1 through3, in certain embodiments, each of the other wings of the aircraft 10may also include one or more of the exemplary features described withreference to FIGS. 10 and 11. For example, in certain embodiments, theaft port wing 26, forward starboard wing 28, and forward port wing 30may each also include forward and aft partial wing assemblies 118, 120with the forward and aft partial wing assemblies 118, 120 having afirst, bottom member and a second, top member configured insubstantially the same manner as the first and second members 144, 150of the forward and aft partial wing assemblies 118, 120 of FIGS. 9through 12.

Inclusion of a forward partial wing assembly 118 including a firstmember and an aft partial wing assembly 120 including a first member inaccordance with an exemplary embodiment of the present disclosure mayallow for the wing to form an exhaust flowpath for the plurality of VTEfans capable of improving performance of the plurality of VTE fans. Insuch a manner, smaller, and less powerful VTE fans may be includedwithin the aircraft 10, while still providing a desired amount ofvertical thrust for, e.g., vertical takeoff and vertical landing.

It should be appreciated, however, that the exemplary diffusion assembly126 described with reference to FIGS. 9 through 12 is provided by way ofexample only. For example, in other embodiments, any other suitableconfiguration may be provided. For example, in other embodiments, theforward partial wing assembly 118 may not include the second member 150,and similarly, the aft partial wing assembly 120 may not include thesecond member 160. Additionally, although for the embodiment depicted,the first members 144, 156 and second members 150, 160 of the forwardpartial wing assembly 118 and aft partial wing assembly 120 generallyextend continuously along the length of the wing 24 (see, e.g., firstmember 144, 156 depicted in phantom in FIG. 9), in other embodiments,the diffusion assembly 126 may instead include a plurality of separatefirst members 144 and/or a plurality of first members 156 spacedsequentially along the length of the wing 24 to form the exhaustflowpath 146 for the plurality of VTE fans 46. For example, the forwardand aft partial wing assemblies 118, 120 may be configured in a similarmanner to the forward and aft partial wing assemblies 118, 120 of FIGS.7 and 8. With such an embodiment, each of the first and second forwardpartial wing assemblies 118A, 118B may include an individual firstmember (e.g., a first member 144A and 144B), and each of the first andsecond aft partial wing assemblies 120A, 120B may include an individualfirst member (e.g., a first member 156A and 156B).

Referring now generally to the various embodiments of the diffusionassembly described herein, it will be appreciated that inclusion of adiffusion assembly defining diffusion area ratio as described herein mayresult in more efficient VTE fans. More specifically, for theembodiments described herein, the diffusion area ratio is greater than1:1. For example, the diffusion area ratio may be greater than 1.15:1,such as greater than about 1.25:1. Further, in certain exemplaryembodiments, the diffusion area ratio may be less than about 2:1. Forexample, the diffusion area ratio may be less than about 1.85:1, such asless than about 1.75:1. (Notably, however, in other embodiments, thediffusion assembly may define other diffusion area ratios less than 1:1,or greater than 2:1.)

Moreover, it will be appreciated that inclusion of a diffusion assemblymay result in a first VTE fan 46-1 of a first plurality of VTE fans 46defining a relatively high power loading during vertical thrustoperations. Power loading, as used herein, refers to a measure of anamount of thrust produced per unit of power applied. More specifically,by utilizing an electric fan as the VTE fan to generate thrust along avertical direction V during vertical thrust operations of the aircraft10, and including a diffusion assembly 126 for defusing an airflow 130from the VTE fan(s) in the manner described herein, the first VTE fan46-1 of the first plurality VTE fans 46 may define a power loadingduring such vertical thrust operations greater than about three poundsper horsepower and up to, or rather less than, about fifteen pounds perhorsepower. For example, in certain exemplary embodiments, the first VTEfan 46-1 may define a power loading during vertical thrust operationsgreater than about four pounds per horsepower and less than about tenpounds per horsepower. More specifically, still, the aircraft 10 may bedesigned for certain flight operations requiring a certain amount ofvertical thrust. For example, in certain embodiments, the diffusionassembly 126 and propulsion system 32 may be designed such that thefirst VTE fan 46-1 of the first plurality of VTE fans 46 defines a powerloading between about six pounds per horsepower and about nine poundsper horsepower, or alternatively, may be designed such that the firstVTE fan 46-1 of the first plurality of VTE fans 46 defines a powerloading between about for pounds per horsepower and about seven poundsper horsepower.

Moreover, it should be appreciated that in certain exemplaryembodiments, each of the first plurality of VTE fans 46 may define sucha power loading during vertical thrust operations, and further that eachof the other VTE fans of the propulsion system may also define such apower loading during vertical thrust operations.

Inclusion of VTE fans defining such a power loading may allow for theinclusion of relatively small diameter VTE fans arranged along a length48 of the aft starboard wing 24, as well as arranged along the lengthsof the other wings. In such a manner, each of the wings may define arelatively high aspect ratio, which may provide for relatively efficientforward flight. More specifically, for the embodiments described herein,such as the exemplary embodiment depicted in FIGS. 1 through 3, the aftstarboard wing 24 defines an aspect ratio greater than about 3:1, suchas between about 3:1 and about 6.5:1. More specifically, for theembodiment depicted, the aft starboard wing 24 may define an aspectratio between about 4:1 and about 5.5:1. The aft port wing 26 may defineaspect ratio substantially equal to the aspect ratio of the aftstarboard wing 24. Further, the forward wings, i.e., the forward portwing 30 and forward starboard wing 28 of the aircraft 10, may define alower aspect ratio than the aft wings, but still a relatively highaspect ratio. For example, the forward starboard wing 28 and forwardport wing 30 each define an aspect ratio between about 1.5:1 and about5:1, such as between about 1.75:1 and about 3:1.

It will be appreciated, that as used herein, the term “aspect ratio,”with reference to one or more of the wings 24, 26, 28, 30, generallyrefers to a ratio of the wing's span to its mean chord.

In sum, it will be appreciated that in various embodiments of thepresent disclosure, an aircraft 10 is provided having a wing extendingfrom a fuselage 18 and a propulsion system 32 having a plurality of VTEfans arranged along the wing. The wing may include one or morecomponents being movable to selectively expose at least one VTE fan ofthe plurality of VTE fans. For example, the one or more components maybe components of a variable geometry assembly 116, which may include,e.g., a forward partial wing assembly 118 and an aft partial wingassembly 120 movable to selectively expose the plurality of VTE fansarranged along the length 48 of the wing. The wing may further include adiffusion assembly 126 positioned downstream of the at least one VTE fanof the plurality of VTE fans and defining a diffusion area ratio greaterthan 1:1 and less than about 2:1.

Moreover, in still other exemplary embodiments, diffusion assembly 126may be associated with a single one of the VTE fans of the firstplurality of VTE fans 46, and a wing may further include a plurality ofdiffusion assemblies, with each of the respective plurality of diffusionassemblies associated with one of the VTE fans of the first plurality ofVTE fans 46. Additionally, or alternatively, the diffusion assembly 126may be positioned downstream of two or more of the VTE fans of the firstplurality of VTE fans 46, such as downstream of each of the firstplurality of VTE fans 46. With such an exemplary embodiment, thediffusion area ratio may be defined relative to each of the plurality ofVTE fans (i.e., a ratio of the cumulative outlet cross-sectional area tothe cumulative inlet cross-sectional area).

It will be appreciated, that in other exemplary embodiments, theaircraft 10 and propulsion system 32 may have any other suitableconfiguration. For example, referring now briefly to FIG. 13, anaircraft 10 including a propulsion system 32 in accordance with anotherexemplary embodiment of the present disclosure is provided. Theexemplary aircraft 10 and propulsion system 32 of FIG. 13 may beconfigured in substantially the same manner as one or more of theexemplary aircraft 10 and propulsion systems 32 described above withreference to FIGS. 1 through 22. For example, the aircraft 10 generallyincludes a fuselage 18 and one or more wings, and defines a forward end20, an aft end 22, a port side 14, and a starboard side 16. Further, theexemplary propulsion system 32 generally includes a power source 36 anda plurality of vertical thrust electric fans (“VTE fans”) driven by thepower source 36. As with the embodiments above, each of the plurality ofVTE fans is electrically coupled to the power source 36 to receiveelectrical power from, e.g., an electric machine 42 or an electricenergy storage unit 44 of the power source 36.

However, for the embodiment depicted, the aircraft 10 does not includefour wings arranged in a canard configuration (compare, e.g., FIG. 1),and instead includes two wings—i.e., a first wing 24 extending from thefuselage 18 of the aircraft 10 on the starboard side 16 of the aircraft10 and a second wing 26 extending from the fuselage 18 of the aircraft10 on the port side 14 of the aircraft 10. Notably, however, in stillother exemplary embodiments, the aircraft 10 may have still othersuitable configurations. For example, in still other exemplaryembodiments, the aircraft 10 may have a blended-wing configuration.

Referring still to FIG. 13, for the embodiment depicted the exemplarypropulsion system 32 further varies from the embodiments of FIGS. 1through 22. For example, the exemplary propulsion system 32 includes afirst plurality of VTE fans 46 arranged generally along a length of thefirst wing 24 and a second plurality of VTE fans arranged generallyalong a length of the second wing 26. However, given that the exemplaryaircraft 10 of FIG. 13 only includes two wings, the propulsion system 32does not include a third or fourth plurality of VTE fans (cf., e.g.,FIG. 2).

Further, as will be appreciated, the pluralities of VTE fans 46, 52 maybe arranged in any suitable manner along the lengths of the respectivefirst and second wings 24, 26. Specifically for the embodiment show, thefirst plurality of VTE fans 46 are arranged in a substantially linearmanner along the length of the first wing 24. By contrast, however, thesecond plurality of VTE fans 52 are arranged in a staggered manner alongthe length of the second wing 26. Although the first and secondpluralities of VTE fans 46, 52 are arranged in different manners for theembodiment shown, such is simply for explanatory purposes. In otherembodiments, the first and second pluralities of VTE fans 46, 52 mayeach be arranged in a linear manner or in a staggered manner along thelengths of the wings 24, 26, or further in any other suitable manner(such as a hybrid linear-staggered configuration).

Additionally, although not depicted in FIG. 13, in certain exemplaryembodiments, the wings 24, 26 may include any suitable variable geometryassembly or assemblies for exposing and/or covering one or more of theVTE fans 46, 52 during operation, such as during vertical flightoperations or forward flight operations, as well as any suitablediffusion assembly or assemblies. For example, in certain embodiments,the wings 24, 26 may include one or more of the exemplary variablegeometry assemblies and/or diffusion assemblies described above withreference to FIGS. 2 through 22.

Further, the exemplary propulsion system 32 depicted includes, a forwardthrust propulsor 34 for generating forward (and optionally reverse)thrust during certain operations. For the embodiment depicted, theforward thrust propulsor 34 is mounted to the fuselage 18 of theaircraft 10 at the aft end 22 of the aircraft 10, and more specificallythe forward thrust propulsor 34 is configured as a boundary layeringestion fan for the embodiment shown. In such a manner, the forwardthrust propulsor 34 may be configured in a similar manner as the forwardthrust propulsor 34 described above with reference to FIGS. 2 through 4.However, in other embodiments, any other suitable forward thrustpropulsor (or propulsors) 34 may be provided, such as one or moreunder-wing, fuselage, or stabilizer mounted forward thrust propulsors,such as one or more turbofan, turboprop, or turbojet engines.

Additionally, as is depicted in phantom, in certain exemplaryembodiments, the propulsion system 32 may further include one or moreVTE fans 47 positioned elsewhere in the aircraft 10, such as in thefuselage 18 proximate the aft end 22 of the aircraft 10 as is depictedin phantom in the embodiment of FIG. 13. In such a manner, such VTEfan(s) 47 may additionally be in electrical communication with the powersource 36 such that the power source 36 may drive the fuselage-embeddedVTE fan(s) 47. Notably, the VTE fan(s) 47 may include any suitablediffusion assembly, such as one or more of the diffusion assembliesdiscussed herein with reference to the VTE fans 46.

In other embodiments, however, still other configurations may beprovided.

Referring now to FIG. 14, a flow diagram is provided of a method 300 foroperating a vertical takeoff and landing aircraft in accordance with anexemplary aspect of the present disclosure. In certain exemplaryaspects, the method 300 may be configured for operating one or more ofthe exemplary aircraft described above with reference to FIGS. 1 through13. Accordingly, in certain exemplary aspects, the aircraft operated bythe method 300 may include a fuselage, a wing extending from thefuselage, and a propulsion system, the propulsion system, in turn,having a plurality of vertical thrust electric fans arranged along thewing.

As is depicted, the exemplary method 300 includes at (302) modifying avariable component of the wing associated with a first portion of theplurality of vertical thrust electric fans relative to a second variablecomponent associated with a second portion of the plurality of verticalthrust electric fans to adjust an exposure ratio of the first portion ofthe plurality of vertical thrust electric fans relative to the secondportion of the plurality of vertical thrust electric fans. In at leastcertain exemplary aspects, the first portion of vertical thrust electricfans may be one or more inner vertical thrust electric fans and thesecond portion of vertical thrust electric fans may be one or more outervertical thrust electric fans (i.e., inner and outer relative to thefuselage). For example, when the plurality of vertical thrust electricfans arranged along the wing includes four vertical thrust electricfans, the first portion of vertical thrust electric fans may be a firstand second vertical thrust electric fan and the second portion ofvertical thrust electric fans may be a third and fourth vertical thrustelectric fan.

More specifically, for the exemplary aspect depicted, modifying thefirst variable component relative to the second variable component at(302) includes at (304) positioning the first variable component in aforward thrust position. More specifically, still, positioning the firstvariable component in the forward thrust position at (304) includes at(306) substantially completely enclosing the first portion of theplurality of vertical thrust electric fans.

In addition, for the exemplary aspect depicted, modifying the firstvariable component relative to the second variable component at (302)further includes at (308) positioning the second variable component in avertical thrust position. More specifically, for the exemplary aspectdepicted, positioning the second variable component in the verticalthrust position at (308) includes at (310) substantially completelyexposing the second portion of the plurality of vertical thrust electricfans in the wing. (Notably, such a configuration may be similar to theconfiguration discussed above with reference to FIG. 8.)

Accordingly, it will be appreciated that in certain exemplary aspects,the first variable component and second variable component may each beconfigured as part of a variable geometry assembly, such as one or morethe exemplary variable geometry assemblies 116 described above. Morespecifically, in certain exemplary aspects, the first variable componentof the wing may be a first partial wing assembly of a variable geometryassembly and the second variable component of the wing may be a secondpartial wing assembly of the variable geometry assembly. For example, incertain exemplary embodiments, the first variable component may be afirst, forward partial wing assembly of a variable geometry assembly andthe second variable component may be a second, forward partial wingassembly of the variable geometry assembly. With such an exemplaryaspect, the first variable component/first, forward partial wingassembly may be spaced (e.g., sequentially) from the second variablecomponent/second, forward partial wing assembly along a length of thewing (similar to the first and second forward partial wing assemblies118A, 118B of FIGS. 7 and 8). However, in other exemplary aspects, thefirst and second variable component may be configured in any othersuitable manner for at least partially exposing and at least partiallycovering up one or more of the first plurality of vertical thrustelectric fans.

Notably, it will be appreciated that as used herein, the term “exposureratio” refers to a relative exposure of the first portion of theplurality of vertical thrust electric fans relative to the secondportion of the of vertical thrust electric fans. For example, theexposure ratio may refer to a comparison of a total area of the firstportion of vertical thrust electric fans which are not covered up by anyportion of the wing (i.e., exposed) to a total area of the secondportion of vertical thrust electric fans which are not covered by anyportion of the wing (i.e., exposed).

Referring still to FIG. 14, the method 300 further includes at (312)providing the first portion of the plurality of vertical thrust electricfans with a first amount of electrical power and providing the secondportion of the plurality of vertical thrust electric fans with a secondamount of electrical power. Given that for the exemplary aspectdepicted, the first variable component is in a forward thrust positionand the second variable component is a vertical thrust position, thefirst amount of electrical power may be less than the second amount ofelectrical power. For example, the first amount of electrical power maybe substantially equal to zero.

By modifying an exposure ratio of the first portion of the plurality ofvertical thrust electric fans relative to the second portion of theplurality of vertical thrust electric fans, the method 300 may provideincreased control for the aircraft during vertical thrust operations.For example, modifying an exposure ratio of the first portion of theplurality of vertical thrust electric fans relative to the secondportion of the plurality of vertical thrust electric fans may allow forthe method 300 to provide an intermediate amount of vertical thrustduring transitional operating conditions, such as transitioning fromforward flight to vertical flight (e.g., during landings), transitioningfrom vertical flight to forward flight (e.g., during takeoffs), etc.Accordingly, it will be appreciated that such intermediate amount ofvertical thrust may be provided by operating one portion of the verticalthrust electric fans at a relatively high power, and operating anotherportion of the vertical thrust electric fans at zero, or substantiallyzero, power (as compared to operating all vertical thrust electric fansat, e.g., half power), which may result in an overall more efficientoperation as the vertical thrust electric fans may generally operatemost efficiently closer to full power.

Moreover, as is shown in phantom in FIG. 14, in certain exemplaryaspects, modifying the first variable component relative to the secondvariable component at (302) may further include at (314) positioning thefirst variable component and a middle position. Positioning the firstvariable component in the middle position at (314) may, in turn, includeat (316) partially exposing the first portion of the plurality ofvertical thrust electric fans and partially enclosing the first portionof the plurality of vertical thrust electric fans. It will beappreciated that in at least certain exemplary aspects, positioning thefirst variable component in the middle position at (314) may also allowfor the method 300 provide an intermediate amount of vertical thrust forthe aircraft using the first portion of the plurality of vertical thrustelectric fans during transitional operating conditions.

Furthermore, referring still to the exemplary aspect of the method 300depicted in FIG. 14, it will be appreciated that in at least certainexemplary aspects, the wing may be a starboard wing, and the pluralityof vertical thrust electric fans may be a first plurality of verticalthrust electric fans of the propulsion system. With such an exemplaryaspect, the aircraft may further include a port wing also extending fromthe fuselage and the propulsion system may further include a secondplurality of vertical thrust electric fans arranged along the port wing.With such an exemplary aspect, as is also depicted in phantom in FIG.14, the method 300 may further include at (318) modifying a firstvariable component of the port wing associated with a first portion ofthe second plurality of vertical thrust electric fans relative to asecond variable component of the port wing associated with the secondportion of the second plurality of vertical thrust electric fans toadjust an exposure ratio of the first portion of the second plurality ofvertical thrust electric fans relative to the second portion of thesecond plurality of vertical thrust electric fans.

In certain exemplary aspects, modifying the first variable component ofthe port wing relative to the second variable component of the port wingat (318) may further include at (320) modifying the first variablecomponent of the port wing relative to the second variable component ofthe port wing in conjunction with the modification of the first variablecomponent of the starboard wing relative to the second variablecomponent of the starboard wing at (302). For example, the method 300may coordinate these modifications such that the exposure ratio of thefirst and second portions of the first plurality vertical thrustelectric fans is substantially equal to the exposure ratio of the firstand second portions of the second plurality of vertical thrust electricfans. Alternatively, the method 300 may coordinate these modificationssuch that the exposure ratio of the first and second portions of thefirst plurality of vertical thrust electric fans is higher than or lowerthan the exposure ratio of the first and second portions of the secondplurality vertical thrust electric fans in order to effectuate amaneuver of the aircraft (e.g., to bank towards a starboard side of theaircraft, or alternatively, to bank towards a port side of theaircraft).

Further, it will be appreciated that in at least certain exemplaryembodiments, the aircraft may include more than two wings with VTE fansattached thereto or integrated therein. For example, in at least certainexemplary aspects, the starboard wing may be an aft starboard wing andthe port wing may be an aft port wing. With such an exemplary aspect,the aircraft may further include a forward starboard wing and a forwardport wing, each also extending from the fuselage at locations forward ofthe aft starboard wing and aft port wing. Further, with such aconfiguration, the propulsion system may further include a thirdplurality of vertical thrust electric fans (or at least one verticalthrust electric fan) arranged along the forward starboard wing, and afourth plurality of vertical thrust electric fans (or at least onevertical thrust electric fan) arranged along the forward port wing. Theforward port and starboard wings may include variable geometrycomponents similar to the aft port and starboard wings. In such amanner, the method 300 may further include modifying a first variablegeometry component of a forward wing (e.g., forward port or starboardwing) relative to a second variable geometry component of the respectiveforward wing to adjust an exposure ratio of a first portion of therespective plurality of vertical thrust electric fans relative to asecond portion of the respective plurality of vertical thrust electricfans. Further, such a modification of the variable geometry componentsof the forward port or starboard wing may be in conjunction with amodification of the variable geometry components of the aft port orstarboard wing (similar to the modifications made at (320) between theport and starboard aft wings). Such may facilitate further maneuveringof the aircraft (e.g., nose up/pulling back, nose down/diving, etc.).

Moreover, referring now to FIG. 15, a flow diagram of a method 400 ofoperating a vertical takeoff and landing aircraft in accordance withanother exemplary aspect of the present disclosure is provided. Incertain exemplary aspects, the method 400 may also be configured foroperating one or more of the exemplary aircraft described above withreference to FIGS. 1 through 13. Accordingly, in certain exemplaryaspects, the aircraft operated by the method 400 may include a fuselage,a wing extending from the fuselage, and a propulsion system, thepropulsion system, in turn, having a plurality of vertical thrustelectric fans arranged along the wing.

As is depicted, the exemplary method 400 includes at (402) modifying afirst variable component of the wing associated with a first portion ofthe plurality of vertical thrust electric fans relative to a secondvariable component of the wing associated with a second portion of theplurality of vertical thrust electric fans to adjust an effective thrustprofile of the first portion of the plurality of vertical thrustelectric fans relative to an effective thrust profile of the secondportion of the plurality of vertical thrust electric fans. It will beappreciated, that as used herein, the term “thrust profile” generallyrefers to an amount of thrust being generated by a given portion ofvertical thrust electric fans in a given direction (e.g., along avertical direction of the aircraft).

In certain exemplary aspects, modifying the first variable component ofthe wing relative to the second variable component of the wing at (402)may include modifying a variable geometry assembly in a manner to adjustan exposure ratio of the first portion of the plurality vertical thrustelectric fans relative to the second portion of the plurality ofvertical thrust electric fans (see, e.g., the exemplary method 300described above with reference to FIG. 14).

However, for the exemplary aspect depicted in FIG. 15, modifying thefirst variable component of the wing relative to the second variablecomponent of the wing at (402) instead includes modifying variablefeatures of the wing configured to effectively increase or decrease anefficiency of the first and second portions of the plurality verticalthrust electric fans, and more particularly, modifying the variablefeatures of the wing configured to increase or decrease a power loadingof the first and second portions of the plurality vertical thrustelectric fans.

More specifically, still, for the exemplary aspect depicted, the firstvariable component is a first diffusion assembly and the second variablecomponent is a second diffusion assembly. The first and second diffusionassemblies may have any suitable configuration for being operablerelative to one another. For example, in certain exemplary aspects, theexemplary method 400 may be utilized with a diffusion assemblyconfigured in a similar manner as the exemplary diffusion assembly 126described above with reference to FIGS. 9 through 12 (e.g., embodimentswherein first members of forward and aft partial wing assemblies includea plurality of first member segments spaced sequentially along alengthwise direction of the aft starboard wing). Alternatively, however,the diffusion assembly 126 may be configured in accordance with anyother suitable embodiment.

Referring back to the exemplary aspect shown in FIG. 15, it will beappreciated that for the exemplary aspect depicted, modifying the firstvariable component relative to the second variable component at (402)includes at (404) positioning the first diffusion assembly in anextended position, and at (406) positioning the second diffusionassembly in a retracted position. Additionally, for the exemplary aspectof the method 400 depicted in FIG. 15, modifying the first variablecomponent relative to the second variable component at (402) furtherincludes at (408) modifying a diffusion area ratio of the firstdiffusion assembly relative to a diffusion area ratio of the seconddiffusion assembly. Notably, modifying the diffusion area ratio of thefirst portion of the plurality of vertical thrust electric fans relativeto the diffusion area ratio of the second portion of the plurality ofvertical thrust electric fans at (408) will additionally (assumingcertain other conditions are remaining constant) modify a power loadingof the first portion of the plurality of vertical thrust electric fansrelative to a power loading of the second portion of the plurality ofvertical thrust electric fans.

It will be appreciated that operating a vertical takeoff and landingaircraft in accordance with one or more of the exemplary aspects of theexemplary method 400 may allow for an increased degree of handling ofthe aircraft by being able to more precisely control an amount of thrustgenerated by the various portions of the plurality of vertical thrustelectric fans arranged along a length of the wing of the aircraft.

Notably, as with the exemplary aspect described above with reference toFIG. 14, in certain exemplary aspects of the method 400 depicted in FIG.15, the wing may be a starboard wing, and the plurality of verticalthrust electric fans may be a first plurality of vertical thrustelectric fans of the propulsion system. With such an exemplary aspect,the aircraft may further include a port wing also extending from thefuselage and the propulsion system may further include a secondplurality of vertical thrust electric fans arranged along the port wing.With such an exemplary aspect, the method 400 may further include, as isdepicted in phantom, at (410) modifying a first variable component ofthe port wing associated with a first portion of the second plurality ofvertical thrust electric fans relative to a second variable component ofthe port wing associated with the second portion of the second pluralityof vertical thrust electric fans to adjust an effective thrust profileof the first portion of the second plurality vertical thrust electricfans relative to an effective thrust profile of the second portion ofthe second plurality vertical thrust electric fans.

In certain exemplary aspects, modifying the first variable component ofthe port wing relative to the second variable component of the port wingat (410) may additionally include at (412) modifying the first variablecomponent of the port wing relative to the second variable component ofthe port wing in conjunction with modifying at (402) the first variablecomponent of the starboard wing relative to the second variablecomponent of the starboard wing. For example, the method 400 maycoordinate these modifications such that the thrust profiles of thefirst and second portions of the first plurality of vertical thrustelectric fans is substantially equal to the thrust profiles of the firstand second portions of the second plurality of vertical thrust electricfans. Alternatively, the method may coordinate these modifications suchthat the thrust profiles of the first and second portions of the firstplurality of vertical thrust electric fans is higher than or lower thanthe thrust profiles of the first and second portions of the secondplurality vertical thrust electric fans in order to effectuate amaneuver of the aircraft (e.g., to bank towards a starboard side of theaircraft, or alternatively, to bank towards a port side of theaircraft).

Further, it will be appreciated that in at least certain exemplaryembodiments, the aircraft may include more than two wings with VTE fansattached thereto or integrated therein. For example, in at least certainexemplary aspects, the starboard wing may be an aft starboard wing andthe port wing may be an aft port wing. With such an exemplary aspect,the aircraft may further include a forward starboard wing and a forwardport wing, each also extending from the fuselage at locations forward ofthe aft starboard wing and aft port wing. Further, with such aconfiguration, the propulsion system may further include a thirdplurality of vertical thrust electric fans (or at least one verticalthrust electric fan) arranged along the forward starboard wing, and afourth plurality of vertical thrust electric fans (or at least onevertical thrust electric fan) arranged along the forward port wing. Theforward port and starboard wings may include variable geometrycomponents similar to the aft port and starboard wings. In such amanner, the method 400 may further include modifying a first variablegeometry component of a forward wing (e.g., forward port or starboardwing) relative to a second variable geometry component of the respectiveforward wing to adjust an effective thrust profile a first portion ofthe respective plurality of vertical thrust electric fans relative to asecond portion of the respective plurality of vertical thrust electricfans. Further, such a modification of the variable geometry componentsof the forward port or starboard wing may be in conjunction with amodification of the variable geometry components of the aft port orstarboard wing (similar to the modifications made at (412) between theport and starboard aft wings). Such may facilitate further maneuveringof the aircraft (e.g., nose up/pulling back, nose down/diving, etc.).

Notably, however, it will be appreciated that in other exemplary aspectsthe present disclosure, any other suitable method may be provided foroperating a vertical takeoff and landing aircraft in accordance with oneor more exemplary embodiments of the present disclosure.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. An aircraft defining a vertical direction and alongitudinal direction, the aircraft comprising: a fuselage; apropulsion system comprising a power source and a vertical thrustelectric fan oriented to generate thrust along the vertical directionand powered by the power source; and a wing extending from the fuselageand including the vertical thrust electric fan positioned at leastpartially therein, the wing comprising a variable geometry assemblyhaving partial wing assembly, the partial wing assembly comprising aframe and a first member, the partial wing assembly moveable generallyalong the longitudinal direction when the variable geometry assembly ismoved between a forward thrust position and a vertical thrust position,the first member moveable relative to the frame to form an exhaust pathfor the vertical thrust electric fan.
 2. The aircraft of claim 1,wherein the partial wing assembly is a forward partial wing assembly,and wherein the variable geometry assembly further comprises an aftpartial wing assembly, wherein the aft partial wing assembly is alsomoveable generally along the longitudinal direction when the variablegeometry assembly is moved between the forward thrust position and thevertical thrust position.
 3. The aircraft of claim 2, wherein thevertical thrust electric fan is substantially completely enclosed withinthe wing when the variable geometry assembly is in the forward thrustposition, and wherein the vertical thrust electric fan is substantiallycompletely exposed when the variable geometry assembly is in thevertical thrust position.
 4. The aircraft of claim 2, wherein the aftpartial wing assembly comprises a frame and a first member movablerelative to the frame to form at least in part the exhaust path for thevertical thrust electric fan.
 5. The aircraft of claim 1, wherein thefirst member is configured to pivot downwardly along the verticaldirection when the variable geometry assembly is moved to the verticalthrust position.
 6. The aircraft of claim 1, wherein the vertical thrustelectric fan defines a fan axis, wherein the first member of the partialwing assembly of the wing defines a first angle with the fan axis whenthe variable geometry assembly is in the forward thrust position and asecond angle with the fan axis when the variable geometry assembly is inthe vertical thrust position, and wherein the first angle is greaterthan the second angle.
 7. The aircraft of claim 6, wherein the firstangle is between about 75 degrees and about 105 degrees, and whereinsecond angle is between about −30 degrees and 75 degrees.
 8. Theaircraft of claim 1, wherein the partial wing assembly further comprisesa second member, wherein the first member is a bottom member and whereinthe second member is a top member, wherein the top member is movablerelative to the frame of the partial wing assembly to at least partiallyform an inlet path for the vertical thrust electric fan.
 9. The aircraftof claim 8, wherein the top member is configured to pivot upwardly alongthe vertical direction when the variable geometry assembly is moved tothe vertical thrust position.
 10. The aircraft of claim 9, wherein thevertical thrust electric fan defines a fan axis, wherein the secondmember of the partial wing assembly defines a first angle with the fanaxis when the variable geometry assembly is in the forward thrustposition and a second angle with the fan axis when the variable geometryassembly is in the vertical thrust position, and wherein the first angleis between about 75 degrees and about 105 degrees, and wherein secondangle is between about 120 degrees and about 180 degrees.
 11. Theaircraft of claim 1, wherein the first member of the partial wingassembly defines a length, wherein the vertical thrust electric fandefines a fan diameter, and wherein the length is at least about 75percent of the fan diameter.
 12. The aircraft of claim 1, wherein thevertical thrust electric fan is a first vertical thrust electric fan ofa plurality of vertical thrust electric fans of the propulsion system,wherein the variable geometry assembly substantially completely enclosesthe plurality of vertical thrust electric fans when in the forwardthrust position, and wherein the variable geometry assemblysubstantially completely exposes the plurality of vertical thrustelectric fans when in the vertical thrust position.
 13. The aircraft ofclaim 1, wherein the wing comprises a rail and an actuator, and whereinthe frame of the partial wing assembly is movable along the rail by theactuator.
 14. The aircraft of claim 1, wherein the partial wing assemblycomprises an actuator, and wherein the actuator is configured to movethe first member downwardly along the vertical direction when thevariable geometry assembly is moved to the vertical thrust position. 15.The aircraft of claim 1, wherein the wing is an aft wing, wherein thevertical thrust electric fan is a first vertical thrust electric fan,and wherein the aircraft further comprises: a second wing coupled to andextending from the fuselage, wherein the propulsion system furthercomprises a second vertical thrust electric fan integrated into thesecond wing and oriented to generate thrust along the verticaldirection, the second wing comprising a variable geometry assemblyhaving a partial wing assembly, the partial wing assembly comprising aframe and a first member, the partial wing assembly of the second wingmoveable generally along the longitudinal direction when the variablegeometry assembly of the second wing is moved between a forward thrustposition and a vertical thrust position, the first member moveablerelative to the frame to form at least in part an exhaust path for thesecond vertical thrust electric fan.
 16. The aircraft of claim 1,wherein the vertical thrust electric fan is a first vertical thrustelectric fan of a plurality of vertical thrust electric fans of thepropulsion system, and wherein the plurality of vertical thrust electricfans are arranged along a length of the wing.
 17. The aircraft of claim16, wherein each of the plurality of electric fans are fixed inorientation within the wing.
 18. The aircraft of claim 1, wherein thehybrid electric propulsion system further comprises a combustion engineand a forward thrust propulsor, wherein an electric power source is anelectric machine driven by the combustion engine, and wherein theforward thrust propulsor is selectively or permanently mechanicallycoupled to the combustion engine.
 19. A wing for an aircraft including afuselage and a propulsion system and defining a vertical direction and alongitudinal direction, the wing comprising: a plurality of verticalthrust electric fans positioned at least partially within the wing andarranged along a length of the wing; and a variable geometry assemblyhaving partial wing assembly, the partial wing assembly comprising aframe and a first member, the partial wing assembly moveable generallyalong the longitudinal direction when the variable geometry assembly ismoved between a forward thrust position and a vertical thrust position,the first member moveable relative to the frame to form an exhaust pathfor at least one of the plurality of vertical thrust electric fans. 20.The wing of claim 19, wherein the partial wing assembly is a forwardpartial wing assembly, and wherein the variable geometry assemblyfurther comprises an aft partial wing assembly, wherein the aft partialwing assembly is also moveable generally along the longitudinaldirection when the variable geometry assembly is moved between theforward thrust position and the vertical thrust position, and whereinthe aft partial wing assembly comprises a frame and a first membermovable relative to the frame to form at least in part the exhaust pathfor the at least one of the plurality of vertical thrust electric fans.